ZA200807114B - Burner - Google Patents

Description

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THIS INVENTION relates to a device which facilitates the controlled combustion of a liquid or gel fuel and to an airflow regulator for such a device. : The Applicant believes that this invention will find particular application in the field of burners for stoves which utilize liquid or gel fuels as energy source. In general, any fuel that may be consumed by means of diffuse combustion can be used. More particularly examples of suitable fuel include alcohol liquids such as methanol, ethanol and the like and gels both bio and synthetic. In addition, the fuels may include kerosene liquids and gels such as paraffin and high paraffin oil as well as bio and synthetic fuels. These stoves typically include a container in which the bulk of the fuel is placed, and a burner unit which is mounted onto this container and facilitates the controlled combustion of the fuel vapor.

According to a first aspect of the invention there is provided a burner for facilitating the controlled combustion of a liquid or gel fuel, the burner including a body having peripherally spaced sets of openings located in the body, each set of openings including an air inlet opening and an associated flame outlet opening.

In one embodiment of the invention each air inlet opening and its associated flame outlet opening may be defined by a hole in the body. )

The burner may include a divider which is interposed between an air inlet opening and an associated flame outlet opening and which extends operatively upwardly away from an operatively upper surface of the body, thereby separating the air inlet opening from the air outlet opening.

The divider may be annular in shape and extend operatively away from an operatively upper surface of the body. oo

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Instead, the divider may be formed by a tab which protrudes upwardly away from the operatively upper surface of the body between the associated inlet opening and flame outlet opening. The tab may be formed by the material which is removed to form the flame outlet openings, the material being cut along part of its periphery and bent about a lower edge thereof upwardly to form the tabs. :

In another embodiment of the invention, each inlet opening and flame outlet So opening in the body may be defined by a single hole in the body, the divider serving to separate the hole into an air inlet section and a flame outlet section.

The body of the burner may be disc-shaped and may have a central member and a peripheral skirt depending from the central member, the air inlet _ openings being circumferentially spaced in the peripheral skirt and the flame outlet : 15 openings being circumferentially spaced in the central member.

The number of air inlet openings may correspond to the number of flame outlet openings and the air inlet openings and flame outlet openings may be in : circumferential register, each air inlet opening and its associated flame outlet oo opening forming a set of openings. | a : A direct distance, as measured across a surface of the body of the burner, between a flame outlet opening and an associated air inlet opening with which the flame outlet opening is in register, may not exceed 8% of the diameter of the burner. More preferably said distance is between 1% and 5% of said diameter.

The central member may taper inwardly away from the skirt toward a central configuration. The central configuration may be, but is not limited to, a planar surface or an outwardly concave dome. | oo oo

An angle at which the central member tapers toward the central configuration may be between 15° and 75° relative to a plane which is perpendicular to an axis of the skirt.

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® | 5 2008/07 114 - : The flame outlet openings may be peripherally located in the tapering : portion of the central member. : "The flame outlet openings may be of any shape. More preferably the flame outlet openings may decrease in width away from the skirt. In one embodiment they may be triangular. In another embodiment they may be rectangular or trapezium shaped. oo oo ~ The air inlet openings may be located in the skirt portion of the body.

The air inlet openings may be of any shape. More preferably the air inlets openings may be rectangular. Co ~The walls of the skirt may be oriented between 45° and 95° relative to a plane which: is perpendicular to an axis of the skirt. Preferably the walls are a. oriented at an angle greater than 60° relative to said axis. More preferably, .the walls may be orientated at an angle of greater than 75° relative to said axis. "The burner may further include a protrusion which extends downwardly from an operatively upper edge of at least one air inlet opening. Preferably such a protrusion extends downwardly from an operatively upper edge of each air inlet opening, the protrusions facilitating the formation of a negative pressure area on the inside surface of the protrusion as air flows around it, thus deflecting the airflow upward towards the associated flame outlet opening. ~The protrusion may be tapered. More preferably the protrusion may be triangular.

The protrusion may act as an automatic re-ignition device for the burner, wherein the pinnacle or apex of a triangular protrusion may accumulate enough heat during the operation of the burner as to provide enough heat for unassisted re<ignition of the air-vapor mixture, should the flame be extinguished at any time during the operation of the burner.

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® ] The burner may further include a regulator which is displaceable to vary the effective sizes of one or more of the air inlet openings and/or the flame outlet openings.

The regulator may include a shell which corresponds in shape to that of the burner body and has air inlet and flame outlet openings corresponding to those of the burner body, the shell being displaceable relative to the body between an open position in which the openings in the shell are in register with those of the burner body and a closed position in which the openings are out of register.

The regulator may be rotatably mounted onto the burner body and may accordingly be rotatably displaceable relative to the burner body between an open position, in which the openings in the regulator are in register with those of the burner body, and a closed position, in which the openings are wholly or partly out of register. -

According to a second aspect of the invention, there is provided an airflow regulator for regulating the rate of combustion in a burner, of the type described, by regulating the airflow to the burner, the regulator including a shell which is concentrically “mountable on the burner body and has a plurality of circumferentially spaced flame outlets and a plurality of circumferentially spaced air inlets provided therein, the number and location of the flame outlet openings and air inlet openings in the shell of the regulator respectively corresponding to the number and location of the flame outlet openings and air inlet openings on the burner body in conjunction with which the regulator is to be operated.

More particularly the regulator shell may therefore be disc-shaped, comprising a vertical cylindrically shaped portion having a closed top. and an open bottom and having peripherally spaced apertures defined therein.

The apertures may respectively function as flame outlets and air inlets

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. ¢ ~The regulator may further include a divider nici roR0. 8.4.02, 1 4 air inlet opening and an associated flame outlet opening of the regulator, thereby separating the air inlet opening from the air outlet opening.

The divider may be annular in shape and may extend operatively away : from an operatively upper surface of the regulator shell.

Alternatively, the divider may be in the form of a tab which protrudes upwardly away from an operatively upper surface of the regulator shell between B an associated air inlet opening and flame outlet opening. - } The tab may be formed by material which is removed to form the flame outlet openings, the material being cut along part of its periphery and bent about a lower a. edge thereof upwardly to form the tab.

The invention will now be described by way of example with reference to the following diagrammatic drawings.

In the drawings:

Figure 1 shows a three-dimensional view of the body of a burner in accordance with the invention; :

Figure 2 shows a three-dimensional view of a regulator which may be used in conjunction with the burner body in accordance with the invention; )

Figure 3 shows a schematic cross sectional view of the burner body or the regulator;

Figures 4 and 5 show three-dimensional views of the operation of the . regulator in conjunction with the burner body; and

Figures 6 and 7 shows a three-dimensional view similar to Figures 4 and 5 of another burner in accordance with the invention;

Figure 8 shows a three-dimensional view similar to Figure 4 of another burner in accordance with the invention; and

Figure 9 shows a three-dimensional view similar to Figure 4 of yet another burner in accordance with the invention.

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, ) | 7 o ; Referring to the drawings and in particular to Figure 1, reference numeral 10 generally indicates a body of a burner in accordance with the invention. The burner body 10 comprises a central member 12 and a peripheral skirt 14 depending from the central member 12. The central member 12 tapers inwardly, Co away from the skirt 14 toward a central configuration 42. A corresponding number of circumferentially spaced triangular flame outlet openings 16 and oo circumferentially spaced rectangular air inlet openings 18 are located in the central member 12 and the skirt 14 respectively, the flame outlet openings 16 and air inlet openings 18 being in circumferential register, i.e. they are arranged in pairs so that the centers of the flame outlet opening 16 and air inlet opening 18 in each pair lie on a common radius. A triangular protrusion 44 extends downwardly from. an operatively upper edge 50 of each air inlet opening 18. The direct distance 46 : between the operatively lower edge 48 of a flame outlet opening 16 and the operatively upper edge 50 of an air inlet opening 18, as measured across the body of the burner 10 does not exceed 8% of the burner body 10 diameter 48 and is more preferably between 1% and 5% of said diameter 48.

Referring in particular to Figure 2, reference numeral 20 generally indicates a regulator in accordance with the invention, the regulator 20 having a body or shell 21 which is of a similar shape and configuration as the burner body 10 in conjunction with which the regulator is to be operated. The regulator shell 21 comprises a central member 22 and a peripheral skirt 24 depending from the central member 22. The central member 22 tapers toward a central configuration 52. A corresponding number of circumferentially spaced flame outlet openings 26 and circumferentially spaced air inlet openings 28 are located in the central member 22 and the skirt 24 respectively, the flame outlet openings 26 and air inlet openings 28 being in circumferential register.

Figure 3 represents a cross-section of a burner body 10 or regulator 20 as represented respectively in Figure 1 and Figure 2. The central member 12, 22 tapers toward a central configuration 42, 52 at an angle 32 which is between 15° and 75°. The central configuration 42, 52 may either be in the form of a planar surface 34 or an outwardly concave dome 36 or a combination of both. The peripheral skirt 14, 24 depends from the central member 12, 22 at an angle 38

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. which may be between 45° and 95° relative to a plane 39 perpendicular to an axis of the skirt 14. In the represented embodiment the angle 38 is 90°.

Referring in particular to Figure 4, reference numeral 30 generally indicates : a bumer comprising a concentric combination of a regulator 20 and a burner body 10. The regulator is dimensioned to fit snugly over the burner body 10 and to be angularly displaceable relative thereto. The regulator 20 is shown in a first position on the burner body 10 wherein the flame outlet openings 26 and air inlet openings 28 on the regulator 20 are respectively in register with the flame outlet openings - 16 and air inlet openings 18 on the burner body 10. . Figure 5 shows the burner 30 of Figure 4 with the regulator 20 having been rotated in a clockwise direction around the central axis of the burner body 10 into a second position, wherein the openings in the regulator 20 and the openings in the burner body 10 are partly out of register.

In use, the burner 30 is positioned on top of an open-topped receptacle containing a liquid or gel fuel. With the regulator 20 in the position shown in

Figure 4 of the drawings, i.e. with the flame outlet openings and air inlet openings in the burner body and the regulator in register, fuel vapour is ignited. Air enters a chamber defined between the burner 30 and the open-topped receptacle through : the air inlet openings 28, 18 where it mixes with fuel vapour and is- ignited. The flames exit the burner through the flame outlet openings 16, 26. It will be : appreciated that with the openings in register as shown in Figure 4 of the drawings, fuel will be burnt and heat given off at a maximum rate. [fit is desired to reduce the rate at which fuel is burnt and heat is given off, the regulator 20 can be angularly displaced relative to the burner body where parts of the air inlet openings 18 and flame outlet openings 16 are covered by the regulator 20 thereby reducing the rate of air flow into the chamber and hence the rate at which fuel is burnt. If the regulator 20 is displaced further such that the air inlet openings 18 and flame outlet openings 16 are completely covered, the flame will be starved of oxygen and will be extinguished. The inventor has found that with the regulator in its fully open position (shown in Figure 4 of the drawings) the use of the triangular ‘flame outlet openings 16 works particularly well. However, when the regulator is

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‘ ¢ 9 . displaced towards its closed position and is in a partially open position (as shown in Figure 5 of the drawings) the inventor believes that it may be preferable to make use of rectangular flame outlet openings 16 as shown by the broken lines in

Figures 1 and 5 of the drawings. Depending on the intended application the optimum configuration can be selected.

It will be appreciated that, in circumstances where it is not required to regulate the heat generated, the burner body could be used as a burner without the regulator. : :

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Further, making use of a bummer body having the curved central region as illustrated in broken lines in Figure 3, reduces the volume of the chamber defined between the burner 30 and the open topped receptacle which results in a faster start-up of the burner, i.e. the time to reach operational temperature is reduced. | : : : As an advantage of the device as described, the peripheral arrangement of air inlet openings and flame outlet openings, being in circumferential register, stimulates the formation of independent combustion systems at each of the flame outlet opening/air inlet opening combinations. This occurs due to air entering through an air inlet opening being directly utilized by the combustion process : taking place at the corresponding flame outlet opening with which the air inlet : opening is in register. The triangular protrusion protruding from the upper edge of the air inlet opening further aids this process by creating a negative pressure area on the inside surface of the protrusion and thereby deflecting the air upward towards the flame outlet. This results in the formation of a steady-state system, wherein the air used by the combustion process is continuously replaced by air entering through the air inlet opening. An optimal amount of air is therefore provided to the combustion process and has more efficient fuel energy utilization to effect. ) : ~~ Due to the formation of independent combustion systems within the device : at each inlet/outlet combination a further advantage is that a variation in the air supply to one combustion system will.not affect the operation of other combustion systems. | | | Lo oo

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By positioning the flame outlet openings 16, 26 towards the periphery of the : burner, the Inventor believes that pots and the like positioned above the burner : will be heated more efficiently. oo

Reference is now made to Figures 6 and 7 of the drawings, in which reference numeral 100 refers generally to another burner in accordance with the invention and, unless otherwise indicated, the same reference numerals used - ] above are used to designate similar parts.

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In this embodiment of the invention, the burner 100 includes a burner body, generally indicated by reference numeral 102, and a regulator, generally indicated by reference numeral 104, having a body or shell 105, which is mounted concentrically on the body 102 for rotational displacement relative thereto about an axis 106. Four generally triangular circumferentially spaced holes 108 are provided in the body 102. Similarly, four corresponding holes 110 are provided. in the regulator shell 105. "An annular divider 112 is attached to an operatively upper surface of the regulator shell 105 and protrudes upwardly therefrom coaxial with the axis 106. The diameter of the divider 112 is selected such that the divider is spaced radially inwardly from the radially outer edges of the holes 108, 110 and extends across the holes in order to divide them into an outer air inlet section, generally indicated by reference numeral 114 and an inner flame outlet section, generally indicated by reference numeral 116. | oo

A handle 118 is attached to the regulator shell 105 in order to facilitate angular displacement of the regulator 104 about the axis 106 relative to the body 102 between an open position (shown in Figure 6), in which the holes 108, 110 are in register and a closed position in which they are out of register and the holes 108 are closed off. In Figure 7 of the drawings, the regulator 104 is shown in an : intermediate position between its open and closed positions. ~~ In use, the burner 100 is used in substantially the identical fashion to that described above. Instead of having separate holes for the air inlet and flame outlet openings, the holes 108, 110 are simply divided into the two sections 114,

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oo , 116 by the divider 112 such that air enters the burner through the air inlet sections 114 and flames exit the burner through the flame outlet sections 116. "The inner area of the divider 112 into which the flame outlet sections 116 of the holes 108, 110 open provides a chimney effect or draw to further assist with the heating of a pot or pan. .

It will be appreciated that, in the case of a burner which does not make use of a regulator 104, the divider 112 could be mounted directly on the burner body . 1020 oo

It will be appreciated, that the divider 112 could also be used with the burner 30. Hence, as indicated in Figure 8 of the drawings, reference numeral 200 refers generally to another burner in accordance with the invention and, unless otherwise indicated, the same reference numerals used above are used to : designate similar parts. The burner 200 is substantially identical to the burner 30 except that it includes an annular ring 112 which is attached to the regulator shell 21 and protrudes operatively upwardly therefrom between the air inlet openings 28 and flame outlet openings 26. The ring 112 provides a chimney effect or draw to further assist with the heating of a pot or pan.

Reference is now made to Figure 9 of the drawings. in which reference numeral 300 refers generally to yet another burner in accordance with the invention and, unless otherwise indicated, the same reference numerals used above are used to designate similar parts.

The burner 300 is similar to the burner 200 except that instead of making use of a continuous ring 112, use is made of a plurality of circumferentially spaced tabs 302 which protrude upwardly from a peripheral edge of the central member 22 of the regulator shell 21 at the base of each flame outlet opening 26 to form a vertically extending divider between the flame outlet opening 26 and the associated air inlet opening 28. In a particular embodiment of the invention, the tabs 302 are formed by leaving the portion of material of the regulator which would be removed in order to form the flame outlet openings 26 attached to the central

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. member 22 at a lower edge thereof and bending the material outwardly such that it extends vertically upwardly. The inventor has found that the provision of the tabs 302 also serve to provide a chimney effect and further improve the efficiency of heating.

The inventor accordingly believes that a burner in accordance with the invention will be more efficient than conventional burners of which he is aware with a resultant cost saving for a user.

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Claims (24)

“ « 13 Ce _— . CLAIMS TL

1. A burner for facilitating the controlled combustion of a liquid or gel fuel, the burner including a body having peripherally spaced sets of openings located in the body, each set of openings including an air inlet opening and an associated flame outlet opening. :

2. The burner according to Claim 1, wherein the body of the burner is disc-shaped and has a central member and a peripheral skirt depending from the central member, the air inlet openings being circumferentially spaced in the peripheral skirt and the flame outlet openings being circumferentially spaced in the central member. Co

3. The burner according to Claim 2, wherein the number of air inlet openings corresponds to the number of flame outlet openings, the air inlet openings and flame outlet openings being in circumferential register, each air inlet opening and its associated flame outlet opening forming a set of openings.

4. The burner according to Claim 3, wherein a direct distance, as measured across a surface of the body of the burner, between a flame outlet opening and an associated air inlet opening with which the flame outlet opening is in register, does not exceed 8% of the diameter of the burner. oo

5. The burner according to Claim 4, wherein said direct distance is between 1% and 5% of said diameter.

6. The burner according to any of claims 2 to 5 inclusive, wherein the central member tapers inwardly away from the skirt toward a central configuration.

7. The burner according to Claim 6, wherein an angle at which the central member tapers toward the central configuration is between 15° and 75° relative to a plane which is perpendicular to an axis of the skirt. H:CvE Specs KDK TRUST Thermoflue Spec MAC/PJV/cve 18/Aug/2008 8:04 AM

, 8. The burner according to Claim 6 or Claim 7, wherein the flame outlet openings are peripherally located in the tapering portion of the central member.

9. | The burner according to any of Claims 2 to 8 inclusive, wherein the flame outlet openings decrease in width away from the skirt.

10. The burner according to any of claims 2 to 9 inclusive, wherein the walls of the skirt are oriented between 45° and 95° relative to a plane which is perpendicular to an axis of the skirt.

11. The burner according to Claim 10, wherein the walls are oriented at oo an angle greater than 60° relative to said axis.

12. The burner according to Claim 10 or Claim 11, wherein the walls are oriented at an angle greater than 75° relative to said axis.

13. The burner according to any of the preceding claims, which further includes a protrusion which extends downwardly from an operatively upper edge of at least one air inlet opening. : 20

14. The burner according to any of the preceding claims, which further includes a regulator which is displaceable to vary the effective sizes of one or more of the air inlet openings and/or the flame outlet openings. oo

15. The burner according to Claim 14, wherein the regulator includes a shell which corresponds in shape to that of the burner body and has air inlet and flame outlet openings corresponding to those of the burner, the shell being displaceable relative to the body between an open position in which the openings in the shell are in register with those of the burner and a closed position in which - 30 the openings are out of register.

16. The burner according to Claim 15, wherein the regulator is rotatably mounted onto the burner body and is rotatably displaceable relative to the burner body between an open position, in which the openings in the regulator are in H:CvE Specs KDK TRUST Thermoflue Spec MAC/PJV/cve 18/Aug/2008 8:04 AM

ET | 15 : : ’ register with those of the burner body, and a closed position, in which the openings are wholly or partly out of register.

17. The burner according to any of the preceding claims, which further includes a divider which is interposed between an air inlet opening and an associated flame outlet opening and ‘which extends operatively upwardly away from an operatively upper surface of the body, thereby separating the air inlet opening from the air outlet opening. x

18. An airflow regulator for regulating the rate of combustion in a burner as claimed in any of the preceding claims by regulating the airflow to the burner, the regulator including a shell which is concentrically mountable on the burner body and has a plurality of circumferentially spaced flame outlets and a plurality of circumferentially spaced air inlets provided therein, the number and location of the flame outlet openings and air inlet openings in the regulator shell respectively corresponding to the number and location of the flame outlet openings and air inlet openings on the burner body. Co

19. The airflow regulator according to Claim 18, which further includes a divider which is interposed between an air inlet opening and an associated flame outlet opening of the regulator, thereby separating the air inlet opening from the air outlet opening.

20. The airflow regulator according to Claim 19, wherein the divider is annular in shape and extends operatively away from an operatively upper surface of the regulator shell. | | ;

21. The airflow regulator according to Claim 20, wherein the divider is in the form of a tab which protrudes upwardly away from an operatively upper surface of the regulator body between an associated air inlet opening and flame ~ outlet opening. oo : 22. The airflow regulator according to Claim 21, wherein the tab is formed by material which is removed to form the flame outlet openings, the

H:.CvE Specs KDK TRUST Thermoflue Spec MAC/PJV/cve 18/Aug/2008 8:04 AM oo 16 “ material being cut along part of its periphery and bent about a lower edge thereof upwardly to form the tab.

23. A burner according to Claim 1, substantially as herein described with reference to and as illustrated in any of the drawings. :

24. An airflow regulator according to Claim 17, substantially as herein : described with reference to and as illustrated in any of the drawings. DATED THIS 18" DAY OF AUGUST 2008 oo | g | , & AD eld APPLICANTS PATENT ATTORNEYS H:CvE Specs KDK TRUST Thermoflue Spec MAC/PJV/cve 18/Aug/2008 : 8:04 AM