NO20201256A1 - Improved stove - Google Patents

Description

Description

IMPROVED STOVE

FIELD OF THE INVENTION

The present invention in general, relates to the technical field of stoves which can generate a flame from a fuel such as for example liquid alcohol and the like. Particularly, the present invention relates to a cooking stove with an improved design that ensures a high burning efficiency under windy conditions, low emission levels, auto turn off features, convenient and safe refueling technology at an economical production cost.

More particularly, the present invention relates to a cooking stove which can generate a flame from a fuel according to the preamble of claim 1.

TECHNICAL BACKGROUND OF THE INVENTION

Cooking stoves, which generate flame by burning of a fuel such as liquid alcohol are well known.

It is of immense importance that these stoves should have adequate burning efficiency for ensuring good quality of the cooked food.

Furthermore, the emission levels must be low for preventing environmental pollution. Further, it is important that substantial amount of fuel should not be spilled while cooking as such an eventuality is likely to result in an accident and also detrimental for the environment.

Additionally, to ensure that there is no hindrance during cooking, the refueling process has to be convenient and safe as well.

With regard to the above aspects, several designs of such cooking stoves have been proposed.

Publication no. WO 2008/058566 discloses a cooking stove in which the distance between the burner and the cookware ensures a proper emission level of carbon monoxide and also ensures high burning efficiency. This arrangement does not appear to be perfect in as much as, it may not be always possible to maintain this distance in practice. In addition, the stove casing described in this publication surrounds the burner so closely at it ́s top surface that the top surface becomes very warm, and may represent a hazard to the user. Further, the regulation of the flame is effected by a reduction in the area from which fuel is supplied, without the corresponding reduction in supply of oxygen that would provide the perfect fuel-air mix necessary for complete combustion and minimal emissions levels.

Published US patent application US2010/0192933 discloses an alcohol stove which has a heating wire located above the opening of the fuel container. When the heating wire is connected to an electrical power source, it evaporates the fuel inside the container by radiation. The fumes areignited as they pass the heating wire and the stove thus ignited.

The arrangement disclosed in US2010/0192933 also does not appear to be perfect, in respect of providing maximum burning efficiency and ensuring low emission level. That apart, the arrangement of the stove requires that it be turned upside down in order for the fuel containers to be removed. This is a disadvantage in that the pot holder must come in contact with the kitchen bench/ floor etc. while it is still hot from previous cooking. In addition there is potential for spillage of fuel from the container while it is loaded upside down. Thus it is impossible for this arrangement to be refueled conveniently and briskly to ensure that the cooking process is not hindered.

The arrangement disclosed in NO20140059A1 describes a stove where the canister may be loaded from the front or the side of the stove. While this does provide a convenient arrangement for refueling, the system can be made safer by preventing the removal of the canister while the stove is still burning. The arrangement described is also of a open or bridge-like construction which is advantageous for front loading of the fuel container, and also maintains a low surface temperature due to good air flow around the stove. However, despite being equipped with a small windshield, the arrangement described also leaves the flame and thus heat transfer to the cookware vulnerable to draft or wind, blowing either around the low windshield shown on top of the stove casing, or underneath the stoves exposed open structure. The result of this vulnerability may be that instead of generated heat being transferred to the cookware, it is instead retained within the body of the stove, which may also damage the stove or represent a hazard to the user. The use of the stove in drafty conditions is very real in developing countries such as Africa, where inhabitants are used to cooking with for example charcoal and thus the need for good ventilation during cooking and the same procedures are used when transitioning to more advanced stoves.

Although the construction disclosed here is described as simple and economical, the arrangement still uses substantial quantities of materials in it ́s construction thus not describing a most economical production method.

The stoves disclosed above also lack a safety cutout designed to turn off the stove and seal the fuel canister in the event of the stove falling or being knocked from it ́s position of use.

In brief, cooking stoves known in the art, which function by burning of fuel such as liquid alcohol, do not teach the combination of high burning efficiency under windy conditions, low emission levels, auto turn off features, convenient and safe refueling technology at an economical production cost.

The cooking stove according to the present invention meets this need of ensuring the high burning efficiency under windy conditions, low emission levels, auto turn off features, convenient and safe refueling technology at an economical production cost. This is achieved by the cooking stove of the present invention by virtue of its improved windshield, chassis, heatshield and burner design and specially constructed fuel container.

The cooking stove of the present invention, by virtue of its unique design meets other associated needs as well, as will be clear from the following description.

OBJECTS OF THE INVENTION

It is the prime object of the present invention to provide a cooking stove that can generate a flame by burning a fuel such as a liquid alcohol or mixtures thereof and the like, which ensures substantially high burning efficiency even in windy conditions, low emission levels, auto turn off features and safe, easy and quick refilling of the fuel container.

It is yet another object of the present invention to provide a cooking stove which ensures that the fuel container remains firmly locked in a position with the fuel refilling opening safely out of sight and inaccessible during cooking.

All through the specification including the claims, the words “fuel”,“ container”, flame”, “cookware”, “regulator”, “lock”, “burners”, “burner tubes” are to be interpreted in the broadest sense of the respective terms and includes all similar items in the field known by other terms, as may be clear to persons skilled in the art.

Restriction/limitation, if any, referred to in the specification, is solely by way of example and understanding the present invention.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a stove for burning liquid alcohol, preferably ethanol, methanol or a mixture of these, comprising one or more burners for generating flames from fuel supplied from a container underneath it, said burner separated from the fuel container by a heatshield. The burner is surrounded by a windshield arranged to protect the flame, with supports atop the windshield for supporting cookware. The arrangement is further optimised by the windshield being partially recessed within the chassis, to best protect the flame, while still constructed in an open manner such that the chassis does not become overheated during the cooking process. Further, the heatshield is arranged such that it is also within the windshield, and arranged above the lowest level of the windshield. A regulator, rotatably connected to the heatshield, is used to control the size of the opening in the fuel container and thus the strength of the flame.

Furthermore, the burner is slideably connected with the heatshield such that movement of the regulator is linked to the vertical position of the burner relative to the heatshield. Thus the air intake is automatically adjusted to match the available ethanol fuel vapor, and thereby ensures that the mixture of fuel and primary air is a dynamic process and balanced to achieve as low emissions as possible.

The stove is also equipped with a safety feature targeted at prevent accidents should the stove be tipped/knocked over. The regulator is biased towards the off position through the use of a spring. The slot in the stove body through which the regulator passes is equipped with several low teeth details, arranged such that the regulator will be held in the desired position during use, for example on high or medium power, but should the stove be knocked to the floor the regulator will disengage from the teeth details and due to the influence of the spring will immediately move to the off position extinguishing the flame and sealing the flow of fuel from the container.

According to a preferred embodiment of the invention, fuel container is rotateably connected beneath the heatshield, and in addition to the central opening beneath the burner, is equipped with a second opening for refilling. This refill opening is hidden and inaccessible when the stove is burning and used for cooking, and may only be accessed when the stove is off and the fuel container is rotated to a new position to expose the refill opening. In addition to the use of mineral wool within the fuel container to provide safe storage of fuel, the lid is equipped with mineral wool to allow the safe inclusion of a visually accessible fill level during container refilling.

The safe and limited access described above is effected by the use of a locking means, which releases the container for rotation only with the regulator in the off position.

Furthermore, the burner is made with a soft transition of the surface between the baseplate and the tube to ensure a fast and undisturbed flow of air and ethanol vapor after it has been mixed below.

BRIEF DESCRIPTION OF THE DRAWINGS

Having described the main features of the invention above, a more detailed and non-limiting description of an exemplary embodiment is given below, with reference to the drawings.

Figure1 is a perspective view of the stove according to the preferred embodiment of the present invention described.

Figure 2 is a frontal cross sectional view of the stove shown in figure 1

Figure 3 is a perspective exploded view of the stove shown in figure 1

Figures 4 & 5 are views of the burner, heatshield and regulator with the regulator in the on and off positions.

Figure 6 and 7 shows the stove equipped with the teeth and spring arrangement described as an auto off feature.

Figures 8 and 9 show the stove equipped with a rotateably connected fuel container with the container in it ́s accessible and inaccessible positions.

Figures 10 and 11 show the locking means used to prevent access to the rotateably connected fuel container, in locked and unlocked positions.

Figures 12 show an underside view of alternate embodiment of the burner. Figure 13 shows a cross sectional view of the same.

Figure 14 shows the chassis and heatshield formed from the waste material removed from the chassis center.

DETAILED DESCRIPTION OF THE INVENTION

The following describes a preferred embodiment of the present invention which is exemplary for the sake of understanding the invention and nonlimiting.

In all the figures, like reference numerals represent like features. Further, when in the following it is referred to “top”, “bottom”, “upward”, “downward”, “above” or “below” , “right” or “left” “front” or “side” and similar terms , this is strictly referring to an orientation with reference to the figure 1, where the “top” is the top portion of figure 1.

It should also be understood that the shape and orientation of the various components may be otherwise than shown in the drawings, without deviating from the principle of the invention. The number of components may also vary other than what is illustrated and disclosed herein and this is within the scope of the present invention. For example, there may be more than one container as shown and described. Similarly there may be more than one burner tube in each stove. these variations are within the scope of the present invention.

Further, for the sake of understanding, the fuel mentioned is liquid alcohol.

Liquid alcohol includes ethanol and/or methanol with for example say around 90% concentration. It is within the scope of the present invention that the fuel may include similar such substances as known to persons skilled in the art and all these fall within the ambit of the present invention.

Figure 1 is a perspective view of a first preferred embodiment of the stove 1. The stove 1 has a chassis 2 with an open, bridgelike construction arranged to be stable during use with four sturdy legs. A heatshield 3 is situated centrally within body 2 positioned such that it sits below the uppermost surface of chassis 2, through a large central hole in chassis 2. A series of holes 3A in a horizontal surface of heatshield 3 allow air to be drawn vertically through the heatshield 3 to then enter a burner 4 positioned centrally atop heatshield 3. A regulator 5 is used to adjust the size of a central opening in the heatshield 3 thus regulating the flow of fuel vapor from container 6 situated below the heatshield 3 arranged to protect container 6 from the heat generated by burner 4. A windshield 7 is arranged such that it surrounds burner 4, and extends both above and below the top surface of chassis 2. A pot support 8 is attached to the windshield 7, allowing cookware of different sizes (not shown) to be positioned at an optimal height above the burner 4. It will be apparent that the substantial windshield 7 that surrounds the burner 4 and ensures stable effect and effective transfer of heat energy to the cookware in drafty or windy conditions. Due to the geometry of pot support 8, cookware of medium or smaller diameter rests inside and below the top edge of windshield 7, and advantageous arrangement whereby hot "flue" gases and flames meet the underside of the cookware before flowing up the sides of the cookware, inside windshield 7. The chassis 2, heatshield 3, burner 4, regulator 5, windshield 7 and pot support 8 may all be preferably made from metal, more precisely thin sheet metal apart from the pot support 8 which may be formed from metal rod. More precisely it is desirable that the metal material is stainless steel to ensure a long lifespan for the stove.

Figure 2 shows a cross section through a frontal plane, centred on stove 1. In this preferred embodiment the fuel container 6 is arranged such that it may be slid forwards out from under chassis 2 for refuelling, the container resting slidably on rails 9. This feature is not consequential to the present invention. The recessed positioning of windshield 7 below the top surface of chassis 2 is an important feature of the stove 1 of the current invention. Under drafty or windy conditions, the geometric relationship between windshield 7, chassis 2, heatshield 3 and container 6 is critical for effective function. Heatshield 3 and the uppermost surface of container 6 must be positioned at or above the lowest level of windshield 7, such that air drawn in through holes 3A enters vertically due to the draft protection afforded by the lower edge of windshield 7. In this embodiment the lowest surface of heatshield 3 equipped with holes 3A is positioned 3mm above the lowest surface of windshield 7. Additionally the vertical arrangement of windshield 7 within chassis 2 (Y) should be such that burner 4 and container 6 are located as low as possible so as to ensure the stability of the stove 1. The extension of windshield 7 above the chassis 2 (X) drives the positioning of pot support 8 and thus the cookware such that this is situated at an optimal height above burner 4, this height also being important for the minimal production of particulate matter or soot during combustion. As shown in Figure 2, it has been found that the ratio of X to Y should preferably be in the ratio of 4:1, and even more preferably in the ratio of 2.1:1.6. More clearly, the percentage of windshield 7 that should be recess below the main upper surface of chassis 2 should be in the range 28-60%. Even more preferably approximately 40% of the windshield should be recessed as described to give the best combination of strength, wind protection, stability and fuel volume.

Figure 3 shows an exploded view of the preferred embodiment described above. A further advantage of the construction shown here is that heatshield 3 may be made from the material removed from chassis 2 -more precisely, the in removing the material that creates the large central hole in chassis 2 heatshield 3 is formed. This is an economic construction that minimises the material required for the stove, especially important if a better quality of material, for example stainless steel is being used. It will be apparent from Figure 3 that the outer shape of heatshield 3 is defined by the shape of the hole or cutout in chassis 2. An important detail to note is that heatshield 3 is not flat but has been formed with several concentric rings at different heights. These provide multiple advantages, the first being to raise the airholes 3A away from container 6 beneath them, the second in reducing surface contact and thus heat transfer between heatshield 3 and container 6. The third advantage being to reduce the outer diameter of heatshield 3 during their formation such as to create space between heatshield 3 and the central hole in chassis 2 to allow space for windshield 7.

A portion of the chassis 2 on the left and right sides of chassis 2 is directed inwards forming handhold areas 2E, which provide an area the user may use to lift the stove 1. Handholds 2E may either be formed inwards from chassis 2 or may be permanently attached to chassis 2 after forming seperately. Handhold areas 2E are in turn equipped with attachment points 2F, which in addition to the attachment points 2G around the top of the large central opening in chassis 2 provide a sturdy and stabilising connection between the parts chassis 2, windshield 7, and heatshield 3. Thus the parts together advantageously create a strong, lightweight construction. It is also worth noting that attachment points 2F and 2G are formed in such a way that they have a minimal surface area in contact with heatshield 7. In this embodiment this is done via a 3d "dimpling" of the surface around the attachment holes, thus both minimising the surface area in contact between the components and creating a small "air gap" between windshield 7 and chassis 2. This minimises the potential transfer of heat from warm components windshield 7, heatshield 3 to the chassis 2 which shall remain cool during use, in order to minimise risks to the user. An alternative to the "dimpling" method of surface contact reduction would be the use of a washer or spacer made from an insulating material, for example a fiber washer, positioned between chassis 2 and windshield 7.

Figure 4 shows an alternate preferred embodiment of the burner 4, heatshield 3 and regulator 5, with the other components removed for clarity. The burner 4 consists of a burner tube 4A affixed to a burner baseplate 4B. The burner baseplate 4B is positioned over the central hole in the heatshield 3 and the corresponding circular opening in the fuel container 6, and the space between the burner baseplate 4B and the central opening in the heatshield 3 allows for air to flow in and mix with the ethanol before it combusts higher up in the burner tube 4A. The amount of air necessary for complete combustion increases as the fuel made available from container 6 increases, fuel availability controlled by the position of regulator 5. Figure 4 shows tabs 3B rising from the upper surface of heatshield 3, each tab 3B equipped with a guide track 3C.

Burner baseplate 4B is equipped with multiple protrusions 4C. In this embodiment the heatshield 3 is equipped with 3 tabs 3B (one hidden behind the burner tube 4 in Figures 4 and 5, with correspondingly three protrusions 4C attached to burner baseplate 4B. Protrusions 4C extend through guide tracks 3C in each tab 3B, an arrangement which allows for a limited rotation of the burner baseplate concentric with heatshield 3. One of the protrusions 4C of burner baseplate 4B is linked to the regulator arm 5A by means of link member 10, thus causing the burner 4 to rotate when the regulator arm 5A is rotated around pivot 5B. Now guide tracks 3C are angled such that any rotation of the baseplate 4B creates a corresponding change in the vertical distance (marked Z in Figure 2) between the underside of burner baseplate 4B and the upper surface of heatshield 3. Regulator 5 is arranged so that the vertical distance Z is at it ́s maximum with the regulator 5 in fully open position as shown in Figure 4. Similarly the vertical distance Z should be at minimum condition when the regulator 5 is in it ́s closed position, as shown in Figure 5. With a fuel container 6 opening in the range of approximately 70-86mm diameter, this vertical distance Z will optimally lie within the range 3-15mm, even more preferably within the range 5-12mm. This link between the chosen effect and the opening of primary air intake ensure a dynamic and in all positions an optimal mix of air and ethanol for a complete combustion, with a corresponding improvement in emissions performance at the different operation levels (low, medium, high power).

Figure 6 shows another preferred embodiment of the invention where the stove is equipped with an auto-off feature. If the stove 1 is exposed to a blow, a fall to the ground or sudden tilting, it is desirable that the flame be extinguished immediately and the flow of fuel vapor from the container 6 halted. This is an important safety feature with regards to the prevention of domestic fires. The stove of the current invention is equipped with a mechanism to effect such a self-extinguishing action. As can be seen in Figure 6, regulator 5 penetrates the chassis 2 via slot 2A,which both allows and limits movement of regulator 5 so that the flame may be adjusted. Figure 6 shows the regulator in off position. In this preferred embodiment, slot 2A is equipped with several teeth 2B arranged such that the regulator will be held in one of several desired positions during use, for example on high or medium power. Figure 7 shows an underside detail view of the relevant area of stove 1. Here we can see that regulator 5 is equipped with an attachment point 5D, to which is attached a spring 11 which is in turn attached to a fixed point on the stove 1, in this case 2C on the chassis 2. As will be apparent, the user accessable portion of regulator 5 is now biased towards one end of slot 2A, in fact the end of the slot defined as the off position where regulator disc 5C closes the central opening in heatshield 3. Accordingly, regulator 5 may be set to for example maximum position when in use, but should the stove be knocked to the floor the regulator will disengage from the teeth details 2B and due to the influence of the spring 11 will immediately move to the off position extinguishing the flame and sealing the flow of fuel from the container 6, a substantial safety improvement. It will be apparent that the position and type of spring 11, and attachment thereof to regulator 5 and a fixed portion of stove 1 shown above are non limiting. For example attachment 5D may indicate a hole or an extension from regulator 5, spring 11 may be a tension, torsion or extension spring arranged to pull or push upon regulator 5 in order to bias the position of regulator 5. The fixed attachment point indicated at 2C may alternatively be located on heatshield 3 or windshield 7 for example.

From Figure 1 it would be also clear that fuel container 3 is located in the lower portion of the stove body.

Figures 8 and 9 show a preferred embodiment of the stove 1 where fuel container 6 is no longer slideably connected with heatshield 3, but instead rotatably connected beneath heatshield 3. Container 6 may now be rotated through a limited angle and is not removable from the stove. In this preferred embodiment, container 6 in addition to the central opening beneath the burner, is equipped with a second opening 6A for refilling. This refill opening 6A is covered by a lid 6B, and is inaccessible when the stove 1 is burning and used for cooking. It may only be accessed when the stove 1 is off and the fuel container 6 is rotated to a new position to expose the refill opening 6A. Figure 8 shows the container 6 in an inaccessible position, whereby the stove 1 may be used safely. Here the regulator 5 is shown in the maximum position, to the left of slot 2A when viewed from the front. Container 6 is equipped with a grip area 6C enabling the user to more easily rotate container 6 from use position (Figure 8) to refill position (Figure 9). As can be seen in Figure 9, in this embodiment container 6 is equipped with an opening 6A to be sealed by lid 6B. In this embodiment both 6A and 6B are equipped with screw threads for sealing, however other engagement mechanisms may also be utilised here, for example bayonet fixings, the hinging of 6B together with a snap closure mechanism etc. Inside opening 6A is located a tubular extension 6D which moves in a telescopic linear fashion to extend above the surface of container 6 thus facilitating easier refilling. To ensure that the container 6 is not refilled with highly flammable fuel while the stove 1 is burning, its rotation is locked while the stove 1 is burning, ie container 6 may not be rotated to the fill position unless regulator 5 is in the OFF position. Likewise, regulator 5 may not be moved from the OFF position unless container 6 is rotated to its use position. It can be seen from Figure 8 that slot 2A is equipped with a recess 2D at the off position / left hand end the function of which shall become apparent. In this embodiment regulator arm 5 is biased downwards by virtue of it ́s metallic nature, and the vertical relationship of pivot point under 5B and the positioning of slot 2A.

As may be obvious it is an important feature that the fuel container 6 is locked in position while the stove 1 is in use, as the rotation to expose the fill opening 6A and filling ethanol while burning would prove a hazard to the user and surrounding environment.

A further advantage with the container described above lies with the telescopic filling tube 6D. The filling of ethanol containers with mineral wool to reduce buildup of ethanol vapor inside the canister for increased safety is known from earlier patents. However, when pouring ethanol fuel into a container 6 filled with mineral wool it is difficult for the user to know when the container 6 is full and the mineral wool saturated, and thus when to stop filling. In this embodiment of container 6, said container is as normal filled with mineral wool (not shown in Figures) apart from the space taken by tube 6D. Now during refilling, tube 6D is drawn upwards by the user to facilitate filling. The user is now able to pour fuel into the opening in the end of tube 6D whereby it flows downwards to fill container 6 from the bottom, saturating the mineral wool as the level rises.

However as the space reserved for tube 6D is now open, the fill level inside container 6 will be visible to the user, and thus they can more easily see when the container has been filled to safe capacity. This capacity may for example be indicated by a line or marking inside tube 6D or by the lowest visible end of tube 6D when it is in it ́s uppermost position. Once the user has filled to the desired level, tube 6D may be reinserted into it ́s recessed position. Lid 6B is then reattached to seal the container 6. A novel feature to note is the inclusion of cylinder 6E under lid 6B. This cylinder 6E is hollow and is filled with mineral wool 6G. This ensures in turn that there are no large air pockets inside the container 6 where ethanol vapor may collect with associated risk of explosion. A slot 6F in cylinder 6E allows air to escape when lid 6B is attached to container 6. It should be noted that slot 6F may also take the form of 1 or more holes to allow air release instead of a slot.

Figure 10 shows the stove 1 with chassis 2 removed for clarity, with container 6 in its Use position and regulator 5 at it ́s Maximum position. We can also see that locking mechanism 12 is provided to ensure container 6 cannot be rotated prior to the flame being extinguished by regulator 5. In this embodiment, locking mechanism 12 is rotatably attached to windshield 7 at pivot 7A. In addition locking mechanism 12 is equipped with a slot 12A and a stopper detail 12B. Regulator 5 penetrates windshield 7, locking mechanism 12 and chassis 2 (not shown here).

Container 6 is equipped with a stop detail 6H, which in this position rests against stopper detail 12B, thus preventing rotation of container 6 to the refill position. Now, due to the downwards bias of regulator arm 5, when arm 5 is rotated to the Off position, it will move downwards to the lowest level allowed by recess 2D. The relative positions of pivot 7A, slot 12A and recess 2D are such that in the off position, locking mechanism 12 will pivot downwards where acted upon by regulator 5. Accordingly stopper detail 12B at the opposite end of locking mechanism 12 will rise as far as it is allowed,thus freeing stop detail 6H and allowing rotation of container 6 to the fill position. The underside of locking mechanism 12 is arranged such that stop detail 6H prevents further rotation of locking mechanism 12 around pivot 7A, thus preventing any release of regulator 5 from the recess 2D. Once container 6 has been refilled to the desired level it may be rotated back to the Use position, whereby the user is again free to move regulator 5 and ignite the stove 1. It should be understood from the functions explained in the preceding paragraphs, that the operation is very convenient and can be done very quickly without causing hindrance to the cooking process, for example the pot need not be removed during refilling.

The aspect defined in the preceding paragraph ensures safe cooking and quick as well as convenient refueling and maintenance of the stove 1.

Figure 12 shows an alternate embodiment of the burner 4 alone, viewed from underneath while Figure 13 shows a cross sectional view of the same. An advantage of this embodiment is provided by the smooth transition 4D between largely horizontal baseplate 4B and largely vertical burner tube 4A. This smooth transition 4D and the slight conical shape of the 4A and 4B have the advantageous effect of centralising and stabilising the flame within the tube 4A. Plate 4E channels the ethanol vapour through multiple openings, in this case four openings, thus creating turbulence in the flow and thoroughly mixing the ethanol and oxygen. Four openings have been found to function admirably, however a similar funtion may also be achieved with between two or more openings. A smooth transition approximating a radius of between 10mm and 30mm has been found to perform well here, the radius size playing a role in determining the resulting diameter of plate 4E and the opening size. 4E is in this embodiment attached to burner 4D by welding, more specifically laser welding. However it will also be obvious that the plate 4E may be affixed by other means, for example the extremities of plate 4E may penetrate burner 4D in such a manner that the two are permanently joined. It is also possible that plate 4E and burner 4D may be produced as a single component, by the process of sintering or 3d metal printing. A further advantage of the embodiment described above is that, with the improved shape of 4D, while the lower outer edge of 4D may remain a controlled distance above the heatshield 3, the smooth transition of 4D provides a larger volume for the combustion chamber than allowed for in burner 4. In addition, the openings in plate 4E may be positioned slightly higher, and be larger than the similar openings in baseplate 4B, allowing an increased flow of ethanol vapour into the combustion zone for improved firepower.

Figure 14 more clearly illustrates the production of heatshield 3 from the material removed in the creation of the large central hole in chassis 2 as described earlier.

While illustrated independently for clarity, any or all of the improvements described here may be incorporated in a single stove embodiment.

From the description hereinbefore it would be clear that all the objects of the invention are achieved.

The present invention has been described with reference to a preferred embodiment and some drawings for the sake of understanding only and it should be clear to persons skilled in the art that the present invention includes all legitimate modifications within the ambit of what has been described hereinbefore and claimed in the appended claims.

Claims (9)

Claims

1. A stove (1) for burning liquid alcohol, preferably ethanol, methanol or a mixture of these, comprising a burner (4) for generating flames from ethanol supplied from a container (6) accessible from the front side of a chassis (2), said burner (4) separated from container (6) by a heatshield (3), said heatshield (3) surrounded by a windshield (7) equipped with supports (8) for supporting cookware, said stove (1) equipped with a regulator 5 to adjust the flow of ethanol vapor from the container (6) and thereby regulate the size of the flame and heating ability,

c h a r a c t e r i z e d in that the windshield (7) is recessed into a central opening in chassis (2) and that the heatshield (3) is equipped with holes (3A) and positioned such that it is below the uppermost main surface of chassis (2) and level with or above the lowest point of the windshield (7).

2. The stove (1) according to claim 1, c h a r a c t e r i z e d in that the movement of the regulator arm (5) adjusts the amount of vapor released from the container (6) and simultaneously adjusts the vertical opening (Z) between the heatshield (3) and the burner baseplate (4B).

3. The stove (1) according to claim 1 or 2, c h a r a c t e r i z e d in that the regulator arm (5) is biased towards the off position by means of a spring (11), and where the regulator (5) is held in one of several cooking effect settings by means of shallow teeth (2B), such that an accidental fall or blow to the stove (1) will cause a release of arm (5) and the extinguishing of the burner (4).

4. The stove (1) according to any of the preceding claims, c h a r a c t e r i z e d in that the ethanol container (6) is equipped with a second opening (6A) for refilling, said opening (6A) inaccessible while the stove (1) is in use but able to be exposed via a rotation of container (6) once the burner (4) is extinguished.

5. The stove (1) according to claim 4, c h a r a c t e r i z e d in that the ethanol container (6) is equipped with a stop detail (6H), the stove (1) is equipped with a locking mechanism (12) and the interaction between (6H) and (12) is such that container (6) may not be rotated from it ́s use position unless regulator (5) is in the off position, and regulator (5) may not be moved from the off position unless container (6) is rotated to the use position.

6. The stove according to any of the preceding claims, c h a r a c t e r i z e d in that the burner (4) is equipped with a smooth transition (4D) between burner tube (4A) and baseplate (4B), smooth transition (4D) approximating a radius of between 10 and 30mm.

7. The stove according to claim 6, c h a r a c t e r i z e d in that in the baseplate (4B) is conical in form and is equipped with a plate (4E), said plate (4E) permanently fixed to burner (4).

8. The stove according to any of the preceding claims, c h a r a c t e r i z e d in that the heatshield (3) is produced from material removed from the chassis (2) in the making the large central hole.

9. The stove according to any of the preceding claims, c h a r a c t e r i z e d in that the canister (6) is equipped with a lid (6B), lid (6B) in turn equipped with a protrusion (6E), said protrusion equipped with a slot (6F) and filled with mineral wool material (6G).