Patent Application
20120097148
This application claims the benefit of DE 102010042872.8 filed on Oct. 25, 2010, the contents of which are expressly incorporated herein by reference in its entirety.
The invention generally relates to a gas burner for a gas cooktop, to a gas cooktop which is provided with said gas burner, and also to a method for operating a gas cooktop of this kind.
Thermogenerators are known per se for generating electrical energy. To this end, a hot side of the thermogenerator is subjected to the action of heat or heated, while the heat is drawn or output on a cold side. However, the degree of efficiency of a thermogenerator of this kind is usually only 3% to 5%, and therefore the amount of thermal energy that has to be conducted by the thermogenerator is considerably more than the amount of electrical energy obtained. On the other hand, a sufficient amount of thermal energy is available in many applications.
DE 10 2007 058 945 A1 discloses installing a thermogenerator on a gas burner in a gas cooktop. There, the thermal energy which is conducted by the thermogenerator is diverted away toward the gas cooktop. The cold side of the thermogenerator therefore faces the gas cooktop which firstly heats up, this being negative. Furthermore, this thermal energy is lost to the cooking process.
The disclosure is generally directed to providing a gas burner, a gas cooktop and also a method for operating a gas burner of this kind as cited in the introductory part and with which problems which arise in the prior art can be avoided and, in particular, an efficient and structurally simple way of generating electrical energy at a gas burner of a gas cooktop by means of a thermogenerator is provided.
Advantageous and preferred refinements of the invention are the subject matter of the further claims and will be explained in the text which follows. In the process, some of the features cited in the text which follows are explained only in respect of the gas burner, the gas cooktop or one of the methods. However, irrespective of this, they are intended to be applicable to the gas burner, the gas cooktop and also the methods. The wording of the claims is incorporated in the content of the description by express reference.
According to one embodiment, a gas burner, which has a gas burner body which is customary per se and has gas outlet openings, has a thermogenerator arranged above said gas burner body. The thermogenerator can be particularly advantageously arranged concentrically relative to the gas burner body and/or have the same shape or the same or a similar size. As a result, it is possible for the hot side of the thermogenerator to be subjected to the action of thermal energy by the gas burner body itself, this thermal energy otherwise being introduced at the top into a cooking vessel which is placed above the gas burner. The cold side of the thermogenerator is, as it were, cooled by this cooking vessel. This occurs either due to the emission of heat to the base of the pot which is located above said thermogenerator or else, in a preferred refinement of the invention, on account of the cold side of the thermogenerator bearing against the base of the pot. This can be achieved in a particularly preferred manner by flexible or resilient holding means which hold the thermogenerator above the gas burner body and primarily push said thermogenerator against the lower face of the cooking vessel.
These and further features can be gathered not only from the claims but also from the description and the drawings, where the individual features can be realized in each case by themselves or in combination in the form of subcombinations in an embodiment of the invention and in other fields and can constitute advantageous and inherently patentable embodiments for which protection is claimed here. The subdivision of the application into individual sections and subheadings do not restrict the general validity of the statements made thereunder.
Exemplary embodiments of the invention are schematically illustrated in the drawings and will be explained in greater detail in the text which follows. In the drawings:
It has been found that although a thermogenerator which has been put in position directly on the upper face of the gas burner body can absorb the thermal energy very well, it is considered to be more expedient to use radiant heat for the input of thermal energy and to design the thermogenerator with its cold side directly against the lower face of the pot for output purposes since, under certain circumstances, it is mechanically relatively difficult to simultaneously achieve abutment against the lower face of a pot which has been placed on in order to draw away the thermal energy on the cold side. A spring device may be provided for this purpose and can be designed in various ways but which, for temperature resistance purposes, is advantageously composed of metal and therefore can be, for example, in the form of a plate spring or helical spring provided on the upper face of the gas burner body.
A thermogenerator is advantageously in the form of a disk, with its diameter being considerably larger than its thickness or height. The thermogenerator is particularly advantageously arranged approximately parallel to the plane of the gas burner openings. This usually also means that it is arranged parallel to a pot base, this being advantageous primarily for good abutment against said pot base.
In one embodiment, provision may be made for the thermogenerator to be larger than the gas burner body or to laterally protrude beyond said gas burner body. Therefore, the gas flames emerging from the gas outlet openings can be used at least partially to heat up the hot side of the thermogenerator, so that the thermal energy can be introduced in a very effective manner. If the hot side of the thermogenerator is located very close to the upper face of the gas burner body, the transfer of the thermal energy is likewise very easily possible and it is possible for this transfer to be achieved even without the gas flame having to directly reach the thermogenerator.
As an alternative embodiment to the above-described options, a lower first heat conduction element can be arranged between the gas burner or the gas burner body and the thermogenerator. This heat conduction element is advantageously likewise in the form of a disk and arranged such that it is approximately parallel to the plane of the gas burner openings, that is to say, preferably also parallel to the thermogenerator, and at a distance therefrom. The first heat conduction element is intended to bear directly against the hot side of the thermogenerator for the best possible introduction of thermal energy. The first heat conduction element can also be larger than the gas burner body, for example as was described above, for a possible design of the thermogenerator, and therefore the gas flames directly heat the heat conduction element. To this end, said heat conduction element can project laterally beyond the gas burner body by at least 10% of the diameter of the gas burner body or of a ring of the gas burner openings, preferably by a maximum of 20%. Therefore, the lower first heat conduction element can, as it were, capture a portion of the thermal energy and pass it to the thermogenerator, this thermal energy being generated by the gas burner by means of the gas flames in order to thus heat the pot, which is placed on, via its pot base.
In another, provision can be made for the lower first heat conduction element to have, in its edge region, holes and/or recesses in the form of incisions with projections located between them. An edge of this kind of the first heat conduction element can be substantially in the form of a toothed wheel. This can serve to heat the projecting projections, as it were, to a particularly pronounced extent by the gas flames running beneath them. Depending on the power configuration, the holes or recesses can be situated over the gas flames, and therefore these flames can burn through substantially between the projections and, as a secondary effect, heat up the projections. This ensures that a large portion of the thermal energy which is generated by the gas burner is introduced into the pot base. As an alternative, provision can be made for the projections to be situated directly over the gas flames or the gas burner openings which form said gas flames. However, said projections are intended to protrude laterally beyond the gas burner body only to such an extent that the projections are heated to a pronounced extent for introducing thermal energy into the thermogenerator at a level which is sufficient at a low power level only when the gas flames are small in accordance with this low power level. If a higher power level is selected, the gas flames burn more vigorously or are longer and extend far beyond the projections which then continue to be heated. However, a large portion of the thermal energy which is generated by the gas flames is then passed, as desired, to the pot base.
In a yet further embodiment, a further upper second heat conduction element can be provided above or on the upper face of the thermogenerator, that is to say on the cold side. The heat conduction element is particularly advantageously likewise in the form of a disk, as are the thermogenerator and the above-described first heat conduction element. The heat conduction element can advantageously also be approximately the same size as the thermogenerator itself, or alternatively also somewhat larger again, similarly to the first heat conduction element. Therefore, the thermal energy can be transferred particularly effectively from the cold side of the thermogenerator to the pot base. However, the upper second heat conduction element should not be excessively large, so that the gas flames which are generated by the gas burner can continue to ensure sufficiently effective and rapid heating of the pot base. The second heat conduction element also serves for the improved conduction of heat, in this case away from the thermogenerator to the pot base.
In another embodiment of a gas burner, said gas burner is a so-called single-ring burner with a single gas burner body and a single group of gas burner openings in said gas burner body, said gas burner openings being provided on the outer circumference of said gas burner body in the form of a ring, as is customary.
A spring device can advantageously also be provided on a removable cover of a gas burner body, for example also equally as a unit together with the thermogenerator itself. This unit may comprise a cover for the gas burner body, possibly with a spring and the thermogenerator and also possibly including the above-described heat conduction elements, and can therefore be fitted and removed. This is advantageous when only one single such unit is intended to be provided for the gas cooktop according to the invention for cost reasons, and therefore said unit is then used in each case on the gas burner which is to be operated.
In another embodiment, the gas burner is in the form of a two-ring burner. The gas burner has an inner gas burner body and an outer gas burner body. In this case, the thermogenerator is arranged above the inner gas burner body since this is usually always in operation when the gas burner is operating. A gas flame is advantageously formed at the inner gas burner body in a manner which cannot be regulated, but rather which always operates with a thermal power which is designed in such a way that the thermogenerator generates a required electrical power. A gas flame is formed at the outer gas burner body in a manner which can be regulated, and therefore, if the intention is to operate with a power which goes beyond the thermal power of the first inner gas burner body, the second outer gas burner body is, as it were, switched on. This can ensure that, during operation of this two-ring burner, the required thermal energy is always present at the thermogenerator and therefore the required electrical power is generated. Operation with a minimum thermal power at the gas burner body is also applicable for the above-described single-ring burner in any case.
In a further embodiment, it is possible to design the thermogenerator itself as a pot support or as part of a pot support of this kind. To this end, the thermogenerator can be arranged on the gas burner such that it cannot move in the vertical direction, so that it is also stable, in order to be able to place a pot on it. The thermogenerator is advantageously arranged centrally over the gas burner body and has outwardly leading connections to support means on the gas cooktop beneath it, advantageously three to provide standing stability. Therefore, yet further bearing points for the pot are provided in an outer region around the thermogenerator, so that said pot does not bear only on the thermogenerator. In this case, the thermogenerator is intended to be thermally insulated as well as possible from the other parts of the pot support, so that the thermal energy which is to be drawn from the cold side is introduced into the pot as far as possible. The situation of too much thermal energy being drawn from the heating process of the pot can be avoided as a result.
As has already been described, the thermogenerator can advantageously be designed in a removable manner on its own or as a unit together with part of the gas burner body, for example the cover of the gas burner body. This is possible, firstly, for a case in which it is not required at all, for example because the gas cooktop is connected to a mains power supply (e.g., household power) system. Furthermore, this can result primarily in a thermogenerator of this kind not being provided on each gas burner of a gas cooktop but rather fewer or, particularly advantageously, only one single thermogenerator being provided.
In the case of a gas cooktop according to one, provision is made for the thermogenerator to have an electrical connection to a power supply means of the gas cooktop. This electrical connection is intended to exhibit sufficient thermal resistance to advantageously be routed laterally away from the thermogenerator, downward, to the gas cooktop. Since it is inevitably also acted on by the gas flames from the gas burner in the process, care should be taken that it also has sufficient thermal insulation in this respect. Firstly, said electrical connection is intended to cross the gas flame as far as possible above said gas flame. Secondly, electrical and thermal insulation means can have a glass fiber fabric, and plastic or the like can be dispensed with, or have only plastic with a high thermal resistance, such as silicone or the like.
The controller of the gas cooktop is advantageously an electronic controller which has, for example, in addition to program sequences which can be stored, touch-operated switches which are electronically triggered and evaluated. Furthermore, energy store in the form of a rechargeable battery is advantageously contained in the power supply or said power supply has a rechargeable battery. Therefore, any excess electrical energy from the thermogenerator which may have been generated can be stored for starting operation of the gas burner or of the gas cooktop, this being required, on account of there being an electronic controller, before the thermogenerator can actually generate electrical energy.
In an advantageous embodiment, the gas cooktop can have electrical ignition devices for igniting the gas burners. Furthermore, devices such as flame monitoring means or the like can be provided.
In another advantageous embodiment, a gas cooktop can have both single-ring burners and two-ring burners, in particular as have been described above.
In a yet further embodiment, the gas cooktop can be designed such that it can be operated completely without an electrical connection to a mains power supply system. Under certain circumstances, it can even be designed entirely without the option of being electrically connected or without a connection cable. In this case, the electrical energy for operating the abovementioned control means and possibly also the gas valves or other functional devices is drawn solely from said rechargeable battery. In this case, the rechargeable battery also has to be kept charged as far as possible. A gas cooktop of this kind can advantageously also be operated in locations or in an environment which have/has a gas supply, for example by gas cylinders, but are/is not connected to the mains power supply system. Therefore, the concepts disclosed herein are also suitable for portable gas cooktops, for example for camping.
It may be advantageous, specifically for charging the above-mentioned rechargeable battery, to design the electrical power of the thermogenerator to be higher than the power actually acutely required in each case by the controller of the gas cooktop or electrical gas valves or the like. In this way, excess electrical energy from the thermogenerator can be stored in the energy storage means for a further operation.
As has been discussed above, electrically or electronically controlled gas valves are advantageously provided in the gas cooktop. These gas valves can be designed such that, in the case of an above-described two-ring burner, only the inner gas burner is ignited and burns with a specific thermal power at a minimum power setting. This thermal power is designed such that the thermogenerator operates effectively and can advantageously generate the required electrical power for supplying the electronic controller or operates with as high a degree of efficiency as possible. Therefore, in addition to power being supplied to the gas cooktop itself, said energy storage means can also be charged. When the gas valve of the inner gas burner is opened further, said inner gas burner burns with a higher thermal power, with the outer gas burner then being ignited with the further increase and it therefore being possible for the thermal power of said outer gas burner to be fully regulated.
Therefore, in a method disclosed herein for operating an above-described gas cooktop, it is not only possible to obtain electrical energy by means of the thermogenerator, without an excessive amount of thermal energy for heating the pot being drawn, but rather, further functions can also be achieved by the thermogenerator. For example, for a pot identification function, a check can be made as to whether a pot is placed over the gas burner by the thermoelectric voltage being monitored. If the cold side of the thermogenerator is specifically not cooled by a pot base which has been placed on or put in position when the gas burner is operating, no thermoelectric voltage or only a very low thermoelectric voltage is produced at the thermogenerator. Since a controller can check whether the gas burner is operating and, with reference to the position of the gas valve, it can also check the gas throughflow rate and the thermal power at which said gas burner is operating. This information can be used to identify that no pot has even been placed on. This can be evaluated by the controller as a pot being missing and possibly be output in the form of a signal or the like.
In a further embodiment of a method for operating an above-described gas cooktop, the thermoelectric voltage at the thermogenerator can again be monitored and therefore the temperature of the pot base of the pot which has been placed on can be monitored. This temperature determines, specifically, the temperature on the cold side of the thermogenerator and therefore the thermoelectric voltage generated. In this case, provision can be made, after a relatively long phase of an approximately constant temperature of the pot base owing to an approximately constant thermoelectric voltage during operation of the gas burner, for the control means to draw the conclusion that the pot which has been placed on has boiled dry if there is a subsequent rapid increase in temperature due to an increase in the thermoelectric voltage. Therefore, the temperature of its pot base increases to a great extent. The controller can then output a corresponding signal and, for example, switch off the gas burner.
In the case of a yet further method disclosed herein for operating a gas cooktop with a two-ring burner, provision may be made for the control means to detect the thermal power at the gas burner. To this end, the gas throughflow rate to the gas burner can be monitored advantageously by detecting the passage or an open position of the gas valve. This can, in turn, be compared with the electrical power which is output by the thermogenerator or the thermoelectric voltage. The result of this comparison can be used to at least approximately determine the temperature of a pot base, in particular the relative profile of said temperature. The measurement variables or the detected and determined values can advantageously be used to regulate cooking processes.
Turning now to the figures,
A heat conduction element 23 is held above the gas burner 14 on the upper face of the gas burner 14 or the gas burner body 15, which upper face can be formed, for example, by a removable cover (not illustrated here) or the like, by means of a spring 21 which is illustrated here only schematically as a helical spring. The heat conduction element 23 is in the form of a disk and is somewhat larger than the gas burner body 15, but not by too much. The heat conduction element is composed of a material which conducts heat well, for example aluminum or copper, and under certain circumstances die-cast metal.
A thermogenerator 25 is arranged on the upper face of the heat conduction element 23 such that it bears flat on said upper face, specifically such that it sits centrally on said upper face and therefore is concentric relative to the gas burner body 15. The thermogenerator 25 is in the form of a disk and is considerably thicker than the heat conduction element 23, but this does not necessarily have to be the case. Connection lines 27 of the thermogenerator are schematically illustrated and emerge from the side of said thermogenerator and are routed to an energy store 29 of the gas cooktop 11. The energy store 29 in turn is connected to the controller 20. The energy store has a rechargeable battery (not illustrated) or some other energy storage means which can be charged. Furthermore, the controller 20 can be supplied with energy not only by the energy store 29, but also directly by the thermoelectric voltage or electrical energy which is generated by the thermogenerator 25.
In order to ensure that the connection lines 27 which, as can be seen, are clearly laterally routed past the gas flames 17 have a sufficient degree of thermal resistance to said gas flames, the connection lines can have a temperature-resistant insulation. This temperature-resistant insulation can be, on the one hand, an oxide surface on a metal, which oxide surface is not electrically conductive or exhibits poor electrical conductivity, so that two metal lines or metal wires emerge from the thermogenerator 25 as connection lines 27. As an alternative, said temperature-resistant insulation can also comprise customary metal wires with a sufficiently good degree of electrical and thermal insulation due to a surrounding glass fiber fabric or the like. As an alternative, high-temperature-resistant silicone mixtures can also be added or used.
Similarly to the lower heat conduction element 23, a further heat conduction element can also be provided on the upper face of the thermogenerator 25, specifically in order to improve the output of the thermal energy from the thermogenerator 25 to the pot base 31. However, this actually makes sense only if this heat conduction element were considerably larger than the thermogenerator, in order to distribute the thermal energy which is output by said heat conduction element over a larger surface area of the pot base 31. Although this would improve the output of thermal energy from the thermogenerator 25 and therefore improve the degree of efficiency of said thermogenerator, it also simultaneously has an adverse effect on the input of heat from the gas burner 14 or the gas flames 17 into the pot base 31, and therefore this is actually inadvisable. Instead, the thermogenerator 25 should have a size such that it has, as is illustrated, a diameter which is somewhat smaller than the gas burner body 15 and therefore the ring of gas outlet openings 16.
The main improvement in the degree of efficiency of the thermogenerator 25 or increase in the electrical power which is generated by said thermogenerator takes place via the lower heat conduction element 23 which is, as it were, heated to a greater extent by the gas burner 14 or the gas flames 17 on account of its relatively large diameter than would be the case for the thermogenerator 25 alone. To this end, the heat conduction element 23 can, as has been described in the introductory part, have a shape which differs from a round disk in line with the ring of gas outlet openings 16. By way of example, projections and recesses in the form of a toothed wheel can be provided, with said projections and recesses advantageously being matched to the gas outlet openings 16. The gas outlet openings 16 determine, specifically, the profile of the gas flame 17. The projections can be situated exactly above the gas outlet opening 16 and therefore above the gas flames 17 in order to achieve particularly good heating. As an alternative, they can extend between said gas flames in order to be heated by them somewhat for sufficiently good introduction of thermal energy into the thermogenerator 25. At the same time, they draw some, but not too much, energy from the heating process of the pot base 31 as a result.
The spring 21, the heat conduction element 23 and the thermogenerator 25 advantageously form, together with the connection lines 27, an independent unit. Each gas burner of the gas cooktop 11 has a unit of this kind, and therefore electrical power for the energy store 29 is also generated each time a gas burner is operation, with all the thermogenerators obviously being connected to the same energy store 29 in this case.
However, in order to save on this expenditure, it is also possible to make provision for this unit to be removed from the gas burner 14 or the gas burner body 15, for example from the removable cover of said gas burner body, or else to be integrally formed with the cover. Furthermore, the connection lines 27 can be long enough to reach each gas burner of the gas cooktop. As an alternative, the connection lines 27 can be inserted and removed via detachable plug connections on the gas cooktop 11 or on the cooktop plate 12 as electrical connections.
This unit with the thermogenerator 25 is then fitted precisely to that gas burner which is intended to be operated. As a result, it is possible to ensure that electrical energy is also always generated when any gas burner of the gas cooktop 11 is burning. The electrical energy from the energy store 29 can also be used to operate the gas valve 19 which is controlled by the controller 20.
A simpler embodiment of the described gas cooktop is a refinement without a heat conduction element or a heat conduction plate. Although this may be less effective because the thermogenerator is only partially and additional non-uniformly heated, a considerably lower-cost design can be achieved on account of the saving on the heat conduction plate.
In a further alternative embodiment of a gas cooktop 111,
The pot support arms 133 are placed radially on the outside on pot support connection pieces 134, with insulating parts 136 being arranged between these two components. The intended result of this is that not too much thermal energy is output to the pot support connection pieces 134, and therefore to the cooktop plate 112, laterally on the outside via the pot support arms 133. The thermal energy would specifically firstly only result in interference or could cause damage in said cooktop plate. Furthermore, it would fail to heat the pot 130.
Connection lines of the thermogenerator 125, and the gas valve, the controller and the energy store according to
One advantage of the arrangement in
Furthermore, the thermogenerator 125 could also be in the form of a continuous closed disk, similarly to in
A thermogenerator 225 with a lower heat conduction element 223a, which is somewhat smaller and is in the form of a downwardly sloping disk, is arranged at the top of the inner gas burner 214a or the gas burner body 215a. The upper face, that is to say the cold side, of the thermogenerator 225 again bears flat and directly against the lower face of a pot base 231 of a pot 230 which is intended to be heated. In this case, the pot 230 is situated on the pot support connection pieces 234 which are illustrated on the outside.
The second outer gas burner 214b has a gas burner 215b with gas outlet openings 216b from which large and long gas flames 217b emerge. While the smaller gas flames 217a of the inner gas burner 214a at least partially act on the heat conduction element 223 or the thermogenerator 225, the outer gas flames 217b of the outer gas burner 214b reach only the pot base 231 or introduce thermal energy only to said pot base. The thermogenerator 225 is therefore supplied or heated only by the inner gas burner 214a.
Similarly to
The operating options in respect of the two gas burners 214a and 214b as two-ring burners according to
Possible evaluation methods at the thermogenerators by the control means for temperature measurement and for pot identification have likewise already been discussed in detail above.
| Number | Date | Country | Kind |
|---|---|---|---|
| DE102010042872.8 | Oct 2010 | DE | national |
