Patent Publication Number: US-2013252183-A1

Title: Gas burner with at least three rings

Description:
The invention relates to a gas burner with at least three flame rings, comprising an inner burner provided on a burner base and having gas outlet orifices that during operation create an inner flame ring, and an annular outer burner provided on the burner base surrounding the inner burner and that has gas outlet orifices on its inner annular periphery creating an intermediate flame ring and gas outlet orifices on its outer annular periphery creating an outer flame ring, the inner burner having it own gas delivery separate from that of the outer burner. 
     Gas burners of this type are known in the prior art and are employed, for example to provide the maximum delivery of heat when all of the at least three flame rings are operating, thereby enabling a rapid heating or even searing of food, while is nevertheless also providing a low-output operating mode. 
     Published document DE 601 12 137 [U.S. Pat. No. 6,325,619], for example discloses this type of generic gas burner in which, however, the intermediate and outer flame ring of the outer burner can only be controlled together in terms of flame size since both flame rings are supplied with gas from the same gas supply chamber. 
     In this known embodiment of a three-ring burner, the gas is delivered to a common annular gas chamber for the intermediate and outer burner cap only at a single location of the annular chamber through a stub line that extends vertically upward from the gas supply into this annular gas chamber. As a result, the distribution of gas is not uniform within the entire annular gas chamber. 
     The supply of secondary air for combustion at the inner and outer flame ring is also only through a single opening in the outer burner at the level of the gas outlet orifices of the outer and intermediate flame ring, with the result that the closed circular configuration of both flame rings is interrupted at this point. The supply of energy is accordingly not maximized and the supply of secondary combustion air is very restricted in flow cross-section. The supply of secondary combustion air is critical especially during high-output operation since then both the inner and the outer flame ring draw secondary air from the same burner region. 
     The object of the invention is to further develop a gas is burner of this basic generic constructive design while also achieving a uniform and maximum gas supply to all flame rings. An additional preferred object is to also optimize the supply of secondary air and thereby provide sufficient air for combustion in all flame rings. A further object is to achieve optimized operating process. 
     At least the first object of the invention is readily achieved by an approach wherein the annular outer burner in a burner of this generic type has coaxial and separate inner and outer annular gas chambers that are downwardly open toward the burner base, the gas outlet orifices of the intermediate flame ring opening into the inner annular gas chamber while gas outlet orifices of the outer flame ring open into the outer annular gas chamber, and each of the separate annular gas chambers of the outer burner being in fluid communication with a respective annular upwardly open gas chamber formed in the burner base and having its own gas supply. 
     As a result, a completely separate gas supply for all individual flame rings is achieved having an especially low overall height for this type of burner since all gas supply lines or gas chambers of all flame rings together share a coaxial interconnected configuration. This also provides without restriction a multi-part design for this type of burner in terms of height, for example at least composed of the burner base and the inner and outer burners installed thereon that as separate components can be separated from the burner base and for example cleaned. 
     Splitting the distribution of the gas to the inner and is outer gas chambers that are coaxial to each other, in particular, annular gas chambers, is affected here right in the burner base. The respective upwardly open separate gas chambers of the burner base are covered by corresponding downwardly open gas chambers for all flame rings, in particular, of the downwardly open annular gas chambers of the outer burner, and thus the gas chambers associated with each other are fluidically connected. 
     This then produces a propagation of the gas in each flame ring from the gas supply provided at the bottom of the burner base up to the upper gas outlet orifices of the respective flame rings, and this creates a uniform static gas pressure at each of the individual gas outlet orifices without generating an excessively large dynamic circular flow of the gas at the plane of the gas outlet orifices, as known in the above-referenced prior art. 
     In a preferred development, provision can be made whereby the annular outer burner is formed by two superimposed annular elements, the upper annular element having the separate annular gas chambers and the respective gas outlet orifices opening into these chambers, while the lower annular element has a number of first passages, in particular, drilled holes between the element&#39;s upper side and lower side on a first outer diameter that fluidically connect the aligned opposing annular gas chambers of the outer flame ring, and has a number of second passages, in particular second drilled holes on a second inner diameter that fluidically connect the mutually associated opposing annular gas chambers of the intermediate flame ring. 
     Dividing the outer burner into two superimposed annular elements creates the opportunity to integrate additional functions in the outer burner. 
     Provision can be made, for example in a first embodiment of a gap formed between the superimposed lower and upper annular elements from the outer annular gas chamber of the upper annular element, which gap is supplied with gas, is circumferential, and opens into the outer periphery of the outer burner formed by the two annular elements. Creating the gap in the connecting region of the two annular elements enables the formed radially outwardly open gap to be located below the gas outlet orifices of the outer flame ring. A generated, preferably completely closed flame ring without separate flames can thereby underlie the flames of the outer flame ring, in particular those generating the main flames of maximum energy, and acting as a supporting flame ring prevent any cut-off of the main flames during maximum operation. 
     Supplying the gap with gas from the outer annular gas chamber can be effected, for example by preventing the axial lower face of the outer wall delimiting this annular gas chamber from at least partially resting tightly against the surface of the lower annular element and thus allowing gas to flow under it. 
     In a preferred embodiment, the lower annular element can be provided with or without the above-mentioned implementation such that the angular distance between the first passages is identical to the angular distance between the second passages. In particular, if the passages are of circular cross-section, the center points of the holes can be radially aligned, i.e., disposed on a radial line. This type of a alignment can in principle also be provided for other cross-sectional shapes. 
     This arrangement provides the opportunity to provide a passage in at least one region, in particular, each region between two first and second circumferentially adjacent passages, which passage extends between the outer and inner annular surface of the lower annular element. These multiple passages that are preferably located at identical distances from each other preferably function to deliver secondary air from an outer region of the gas burner to a region between inner burner and outer burner so as to supply the inner and intermediate flame rings with secondary air. 
     The supply of secondary air is effected here radially from outside inward on a plane below all the gas outlet orifices of all the flame rings, where a maximum opening cross-section is achieved when a passage is provided in each of the above-referenced regions. In contrast to the above-referenced prior art, a sufficient supply of secondary air to the inner burner and the intermediate flame ring is thus achieved even during maximum operation. 
     In addition, provision can be made in preferred embodiment whereby the lower surfaces of the annular gas chambers are located in the burner base in planes that are oppositely inclined from the horizontal. This enables each annular gas chamber of the burner base to have a maximum depth in the region of its own gas supply, and to have a minimum depth in the opposing region, in particular, at the site of the gas supply for the respective other annular gas chamber. The volume or flow cross-section of the annular gas chamber thus decreases with increasing distance from the gas supply, and this supports the distribution of the gas. 
     Provision can be made in a gas burner of the type according to the invention whereby the flame rings independently supplied with gas are all supplied with gas at a maximum level starting from an initial position of a control element, in particular, of a knob or slider control or plus/minus button, of at least one valve, and by adjusting the control element in one constant direction starting with the outer flame ring and then with the intermediate flame ring, the flame size and thus the output of the respective flame ring is turned down until the flame is extinguished, or is turned up in the opposite direction. 
     In other words, all of the flame rings are initially operated on maximum, and by moving the control element (or actuating only the minus button) at first only the outer flame ring is turned down in terms of flame size/output up to the point of extinguishing the outer flame ring before any control of the intermediate flame ring is effected. 
     Once the outer flame ring is extinguished, the intermediate flame ring is turned down from its maximum output to its minimum output, and finally until it is extinguished. 
     As a result, provision can be made whereby in response to a further movement (including minus buttons) the inner flame ring is also turned down from its maximum output to its minimum output, however, this flame ring is not caused to be extinguished in a first possible embodiment, whereas in another second embodiment it too can be extinguished. 
     This first embodiment has the advantage that when starting from a minimum output of the inner flame ring this output can again be turned up without reignition by moving the control element (for example including actuating a plus button) in another, in particular, opposite direction—after which in response to a further movement/actuation of the control element in the direction of higher output levels a cross-ignition is then effected first to the intermediate flame ring and is turned up to the ring&#39;s maximum output, whereupon a cross-ignition is then effected to the outer flame ring, the output of which can then be turned up. In order to affect the cross-ignition from the intermediate flame ring to the outer flame ring, a cross-ignition slit can be provided in the surface of the annular outer burner. 
     In a second embodiment, provision can be made whereby, after all burners or flame rings are extinguished, ignition is automatically effected first of the inner flame ring at minimum output in response to moving/actuating the control element in the direction of higher output levels, whereupon an increase in the output and the cross-ignition stages is effected as described for the first embodiment. 
     In another embodiment, provision can be made whereby the inner flame ring is operated continuously with the same flame size independently of the flame-size setting for the other flame rings when the outer and intermediate flame rings are regulated one after the other, i.e., successively, as described above. 
     In another embodiment, provision can be made whereby the control element, for example a slider control or a knob or a plus/minus button unit, can be moved back and forth between two end positions, wherein each end position can constitute a start position, and thus an ignition of all flame rings is effected or can be effected at maximum output (for example by pressing the control element, or also automatically) starting from each of the two possible end positions, and in response to moving/actuating the control element in the direction of the other end position a successive turning-down of the individual flame rings is effected starting in the outer flame ring through the intermediate flame ring to the inner flame ring respectively until they are extinguished, in particular, as described above. 
     There is no need in this method to move the control element back to a predefined initial position after all flame rings are extinguished since the same control sequence is performed in each case starting from both end positions. If, however, the turning-down action is not effected up to the point of also extinguishing the intermediate flame ring—in other words, this ring thus remains at least at a minimum output stage—then moving the control element back opposite to the previous direction that decreases output now causes the output of the individual flame rings to be turned up successively one after the other, as was described in the case of the above embodiments. 
     In particular, provision can be made whereby one control element does not move one valve mechanically to regulate the gas supply for all flame rings, but instead provides electrical control signals for an actuator that actuates the at least one valve. 
     As a result, only one regulating or control element is required for all embodiments in order to move this type of burner from the maximum position to the minimum position, wherein a sufficient supply of gas and air is ensured in the maximum position, and the bottom of a cooking pot located on the burner has the maximum level of flames applied to it from three flame rings. 
    
    
     
       The following describes a preferred embodiment in more detail based on the following figures. Therein: 
         FIG. 1  is a side sectional view of a gas burner according to the invention; 
         FIG. 2  is a view from below along section plane A-A of  FIG. 1 ; 
         FIG. 3  is a top view of the gas burner in which the upper annular element of the outer burner has been removed. 
     
    
    
       FIG. 1  is a sectional side view showing the essential constructive details of a gas burner according to the invention. Seen here is a burner base  1  on which an inner burner is provided approximately centrally that is supplied from below with gas from the burner base through a gas chamber  2   b . The connectors for the gas supply are located here outside the paper plane and are thus not shown. Together with  FIG. 1 , the details are also described in connection with  FIGS. 2 and 3 . 
     The inner burner  2  here has a lower part that is, for example permanently attached to the burner base  1  and a cover with gas outlet orifices there can be placed thereon. 
     The inner burner  2  is surrounded by an annular outer is burner  3  that here has two parts one atop the other, that is a lower and an upper annular element. The upper annular element  3   c  has gas outlet orifices on its inner and outer peripheries, as well as two annular gas chambers  4   a  and  4   b  that are coaxial to each other in the lower surface and downwardly open. The gas outlet orifices  3   b  of the outer flame ring open into the outer annular gas chamber  4   b . The gas outlet orifices  3   a  of the intermediate flame ring open into the annular inner gas chamber  4   a  that is similarly downwardly open. The inner annular chamber  4   a  has a smaller radius than the outer annular chamber  4   b.    
     In order to provide a flow connection to the respective gas outlet orifices, the burner base has corresponding downwardly annular gas chambers  6   a  and  6   b . The gas connection between associated corresponding annular gas chambers  4   a ,  6   a , and  4   b ,  6   b  is effected here completely through a lower annular element  3   d  that for this purpose has a number of drilled holes  7  that are arrayed in a circle and aligned with outer two annular outer chambers  4   b  and  6   b , and drilled holes  8  that are arrayed in a circle and aligned with the annular inner gas chambers  4   a  and  6   a . These holes  7  and  8 , preferably run perpendicular to the surface of the annular element  3   d  and thus create flow passages for conducting gas from each annular gas chamber  6   a  and  6   b  in the burner base to the respective annular gas chamber  4   a  and  4   b  in the upper annular element  3   c.    
       FIGS. 2 and 3  are axial views of these holes—as viewed, respectively, from below and from above. It is evident here that the inner holes  8  located can be of smaller flow cross-section than the outer holes  7 . 
     Passages  9 , which are formed by holes, run here between the holes  7  and  8 , in particular, essentially centrally in terms of the thickness of annular element  3   d , so as to deliver secondary air from the outer surface of the burner to the inner burner  2  and the intermediate flame ring. 
     The gas outlet orifices  3   a  of the intermediate flame ring are located here on a frustoconical surface of the upper annular element. The holes of the gas outlet orifices to the annular gas chamber  4   a  can be perpendicular to the frustoconical surface. 
     Each gas supply here can include its own gas/primary-air mixture, which is not shown in the figures. The sequence of the gas supply to the three flame rings can optionally be regulated by means of only one control element, as is described in the background section.