EP2661585B1 - Burner arrangement for a mobile heatable device, in particular for a mobile cooking device - Google Patents

Description

The present invention relates to a burner assembly for a mobile heatable device, in particular for a mobile cooking appliance, with a burner for generating a flame, with a combustion chamber, in which the burner opens with the flame, and with an exhaust pipe, which from the combustion chamber to a Exhaust gas outlet leads, wherein the exhaust pipe has a defined first line length, further comprising a bypass line leading from the burner to the exhaust gas outlet, wherein the bypass line has a defined second line length which is shorter than the first line length. The invention further relates to a cooking appliance with such a burner arrangement.

Such a burner arrangement is made WO 2010/012493 known.

EP 1 591 012 A1 describes an oven for a mobile kitchen field with a burner as a heating source for heating the oven. Flame-guiding parts of the burner are arranged in the interior of a space separate from the baking chamber combustion chamber. The burner and the combustion chamber are located below the baking chamber, so that rising heat of the combustion chamber heats the baking chamber. The combustion chamber itself has a cuboid housing with an upper side, on which a total of six outlet openings are arranged. Each outlet opening is connected to an exhaust pipe. The total of six exhaust pipes are guided vertically upwards at the rear of the cooking chamber and act as a heat exchanger, which heats the cooking chamber. At the upper end of the oven, the six exhaust pipes end in a common exhaust outlet.

The known burner assembly and thus provided cooking appliance have in practical operations away from civilization, especially in the catering of soldiers in military operations, as robust and operational proved. However, the production of the known burner assembly is quite complicated and expensive.

The aforementioned WO 2010/012493 A2 discloses a heat exchanger system for a cooking appliance in which emit two exhaust pipes from a burner. The first exhaust conduit forms a loop which is bridged by the second exhaust conduit so that the second exhaust conduit forms a bypass conduit for the loop. The purpose of this arrangement is a self-regulation of the flow velocity in the first exhaust pipe to minimize the risk of noise and local overheating. By the speed control, an optimal efficiency of the heat exchanger system should be achieved.

The German utility model G 90 02 743 U1 discloses a device for generating heat by flameless combustion of a fuel in a gas stream. In one embodiment, it is an exhaust gas catalyst in a motor vehicle. In another embodiment, it is a mobile heater, such as a heater fan for warehouses or auxiliary heating for motor vehicles. The utility model describes an exhaust pipe from which a loop branches off. In the loop, a catalytic combustion is to be caused by feeding a fuel, to generate in this way heat energy for the catalytic converter or a heat exchanger. Since the heating of the gas flow is associated with an increase in the internal pressure which must be counteracted by the outflow of gas, the utility model mentions automatic overpressure safety valves. Further details of these valves are not disclosed.

Against this background, it is an object of the present invention to provide a burner assembly for heating a mobile heatable device, in particular a mobile cooking appliance for cooking food, which allows cost-effective production of the burner assembly itself and thus the heated device. In addition, the new burner assembly should be able to To heat a device designed for mobile applications as efficiently as possible and with the robustness required for mobile applications.

According to one aspect of the invention, this object is achieved by a burner assembly of the type mentioned above, wherein the exhaust pipe is longer by a factor of 10 or more than the bypass line, and with a valve closure which normally closes the bypass line, wherein the valve closure so pressure controlled is that it automatically opens the bypass line at a defined pressure in the combustion chamber, so that the bypass line opens when igniting the burner and the exhaust pipe is bridged while the bypass line is closed during continuous operation of the burner.

The new burner assembly thus has at least two lines through which exhaust gas can pass from the combustion chamber to an exhaust gas outlet. However, the bypass line is much shorter than the actual exhaust pipe. The short bypass line bridges the long exhaust line by leading from a position near the burner as short as possible to the exhaust outlet. The actual exhaust pipe is much longer than the bypass line, so that the exhaust gas from the combustion chamber via "detours" is guided to the exhaust outlet. Bypass line and exhaust pipe are parallel in terms of their inputs and outputs, so that the short bypass line can short-circuit the long exhaust pipe in a sense. In this case, the exhaust pipe is by a factor of 10 or more longer than the bypass line.

The new arrangement has several advantages. On the one hand, the exhaust pipe can be used very efficiently as a heat exchanger due to its "excess length". It is particularly advantageous if the exhaust pipe is guided in a plurality of curves and / or loops, such as meandering, wave and / or helical, in order to integrate a large line length of the exhaust pipe in a compact design. The large cable length provides a large surface area at which a direct Heat transfer from the hot exhaust gases of the burner to the surrounding air or another medium to be heated can take place.

However, a long exhaust pipe can cause problems with the ignition of the burner, which can be so serious that the burner under unfavorable conditions, especially in a cold start at freezing temperatures, can not accommodate stable operation. Therefore, the new burner assembly has a short bypass line in addition to the long exhaust line. The pressure surge occurring when igniting the burner can be rapidly reduced via the short bypass line, which allows a reliable starting of the burner and a stable burner operation just in the first moments after the ignition of the flame.

In addition, the new burner assembly can be relatively easily and inexpensively manufactured, especially when a long pipe is bent into a shape advantageous for the exhaust pipe. In the preferred embodiments, the burner assembly has exactly one exhaust pipe, which is bridged by exactly one bypass line. The new burner assembly can be made very inexpensively in this case with few components. Independently, the new burner arrangement can be realized very simply as a self-supporting, inherently stable heating module due to the two functionally parallel, but differently long lines that can be installed as a whole (in one piece) in a cooking appliance. Therefore, the new burner assembly also allows a cost-effective production of the heated device.

In addition, the burner assembly has a valve closure which closes the bypass line as a rule.

This embodiment makes it possible to limit the effects of the bypass line to those scenarios in which the bypass line offers advantages over a burner arrangement without a bypass line. In particular, this embodiment makes it possible to open the bypass line for igniting the burner to the thereby resulting pressure surge quickly dissipate, while the bypass line is closed during continuous operation of the burner, so that the exhaust gases of the burner are completely guided by the long exhaust pipe. Thus, this embodiment provides even greater efficiency in heating a medium in the heated device.

Finally, the valve closure is pressure-controlled in such a way that it automatically opens the bypass line at a defined overpressure in the combustion chamber.

The defined overpressure in the combustion chamber, at which the valve closure is to open automatically, is any combustion chamber pressure which exceeds the normal pressure in the combustion chamber before the ignition of the burner and / or the normal pressure within the combustion chamber in the stationary operation of the burner. Preferably, the opening pressure of the valve closure is greater than or at least equal to the ambient pressure outside the exhaust pipe. This embodiment allows a very cost-effective implementation and a particularly stable operation under changing conditions of use.

In a further embodiment, the bypass line has an end with a peripheral edge, wherein the valve closure rests on the peripheral edge as a rule. Preferably, the valve closure is located directly on the peripheral edge. Furthermore, it is preferred if the valve closure is a valve flap.

In this embodiment, the valve closure abuts a relatively sharp edge when the valve is closed. When opened, the valve closure is removed from the peripheral edge. When closing the valve, the can advantageously be done by a compression or tension spring and particularly advantageous by gravity, proposes the valve closure to the sharp edge. The embodiment has the advantage that soot formation on the valve closure is knocked off by the closing operation. Accordingly, this embodiment allows a cost-effective manner a self-cleaning valve closure.

In a further embodiment, the bypass line and the exhaust pipe each have an opening cross-section, wherein the opening cross-sections are approximately equal.

Alternatively, it is conceivable in other embodiments that the bypass line has a substantially smaller or substantially larger opening cross-section than the exhaust pipe. In contrast, the preferred embodiment allows a very stable and cost-effective implementation of the new combustion arrangement, wherein the bypass line on the one hand is large enough to quickly dissipate a pressure surge occurring in particular when igniting the burner. On the other hand, this embodiment contributes to the hot exhaust gases of the burner in stationary operation as completely as possible to lead through the long exhaust pipe to achieve efficient heating within the heated device.

In a further embodiment, the combustion chamber is a substantially cylindrical tube having a first end and a second end, wherein the burner protrudes into the tube at the first end, and wherein the exhaust pipe begins at the second end. In preferred embodiments, the combustion chamber tapers at the second end to the exhaust pipe. Furthermore, it is preferred if the exhaust pipe has at least two mutually opposite pipe sections, in which the hot exhaust gas of the burner is guided in mutually opposite directions.

This embodiment allows a very cost-effective implementation and a very compact design. A tapered to the exhaust pipe Second end also contributes to a low wear of the combustion chamber by scaling.

In a further embodiment, the exhaust pipe forms at least one loop, in particular a helix, which wraps around a first open eye.

The "open eye" is a free area that the exhaust pipe wraps around once or several times. In the preferred embodiments, the exhaust conduit forms a helix with multiple turns that loop around the open eye several times. The embodiment allows a very advantageous mounting of a fan within the open eye, so that a heated by the exhaust pipe medium, in particular air, can be circulated directly in the vicinity of the exhaust pipe. This leads to a very efficient heating, as in particular in an oven, a steam cooker or a combined steam and baking device (combination device) is beneficial.

In a further embodiment, the exhaust pipe forms a second loop, which wraps around a second open eye.

This embodiment allows an even more efficient heating of a large amount of circulated air or other medium in conjunction with a very compact design of the new burner assembly.

In a further embodiment, the at least one loop (preferably helix) is arranged directly next to the combustion chamber. In the preferred embodiments, a second loop / coil is disposed slightly offset adjacent the first loop and adjacent the combustion chamber.

These embodiments allow a particularly stable and compact design of the new burner assembly with a large surface area for a efficient heat transfer and the ability to position one or more blowers directly "within" the burner assembly.

In a further embodiment, the bypass line is a largely straight pipe section. In some embodiments, however, the end of the bypass line remote from the burner may be bent, in particular to form a horizontal support for the valve closure. In these embodiments, however, the bent end has a line length that is small compared to the total length of the bypass line, in particular less than 10%, so that these embodiments fall under the present embodiment.

In this embodiment, the bypass line is just so long that it can effectively bridge the exhaust pipe. As a result, this design contributes to effectively dissipate a pressure surge when igniting the burner, while the efficiency of the burner assembly is affected by the bypass line at best to a small extent.

In a further embodiment, the burner assembly has a sump having a first tube opening, a second tube opening and a third tube opening, wherein the bypass line opens into the first tube opening, wherein the exhaust line opens into the second tube opening, and wherein the third tube opening leads to the exhaust gas outlet. Preferably, the above-mentioned valve closure is arranged inside the collecting container. In one embodiment, the sump is a substantially cuboid box having a first outer side in which the first and second tube openings are juxtaposed, and a second outer side in which the third tube opening is arranged.

These refinements enable a very simple, cost-effective and effective combination of the exhaust gas line and the bypass line in the region of the (common) exhaust gas outlet. The sump makes it special possible to integrate the valve closure cost-effective and protected from mechanical damage in the new burner assembly.

Particularly preferred is the use of the new burner assembly in a cooking appliance for cooking food, especially in an oven, Dampfgargerät and / or combination device with Dampfgar- and baking function. Preferably, such a cooking appliance has a fan, which is looped around by the exhaust pipe. In principle, however, the new burner arrangement can also be used in other heatable devices, such as in devices for heating water or in air heaters for heating tents, mobile containers and other recreation rooms for people.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the respectively indicated combination but also in other combinations or alone.

Fig. 1

ein Gargerät, in dem ein bevorzugtes Ausführungsbeispiel der neuen Brenneranordnung zur Anwendung kommt, in einer Ansicht von schräg vorne,

Fig. 2

das Gargerät aus Fig. 1 in einer geschnittenen Darstellung,

Fig. 3

ein bevorzugtes Ausführungsbeispiel der neuen Brenneranordnung,

Fig. 4

die Brenneranordnung aus Fig. 3 in einer teilweise geschnittenen Detaildarstellung, und

Fig. 5

ein weiteres Detail der Brenneranordnung aus Fig. 3 und 4 in einer vergrößerten, geschnittenen Darstellung.

Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. Show it:

Fig. 1

a cooking appliance, in which a preferred embodiment of the new burner assembly is used, in a view obliquely from the front,

Fig. 2

the cooking appliance off Fig. 1 in a cut view,

Fig. 3

A preferred embodiment of the new burner assembly,

Fig. 4

the burner assembly off Fig. 3 in a partially sectioned detail, and

Fig. 5

another detail of the burner assembly Fig. 3 and 4 in an enlarged, cut representation.

In the Figures 1 and 2 an embodiment of a preferred cooking appliance with the new burner assembly is designated in its entirety by the reference numeral 10. The cooking appliance 10 is here a combination device that can be used both as an oven and as a steamer including a combined operation. In the preferred embodiment, the cooking appliance 10 is configured for mobile use, in particular for use in a mobile field kitchen for military and / or humanitarian non-civilian missions. The device requires a simple power connection, such as a 220V or 110V connection, for the electrical supply of the device-internal control device and the electrical units, such as blower, water pump, display and control panel etc. The heating power of the device is generated by means of a burner, the is integrated into the device 10 in the manner described below.

The cooking appliance 10 has a device housing 13, in which a cooking chamber 12 for receiving commercially available cooking shells 14, baking trays or gratings is formed. The cooking chamber 12 has a front side, which can be closed by a door 16, and a rear side. At the rear of the cooking chamber 12, an embodiment of the new burner assembly 18 is disposed behind a partition, not shown here.

How to get in Fig. 3 can recognize, the new burner assembly 18 has a burner 20, which is arranged here at the upper end 21 of a combustion chamber 22, and an exhaust pipe 24, in which the lower end 25 of the combustion chamber 22 passes. The exhaust pipe 24 forms two coils 26, 28, each with several turns wrap around an open "eye" 30. In the cooking appliance 10 is in the eyes 30 of the two coils 26, 28 each have a fan 32, 34 is arranged, which circulates the heated by means of the exhaust pipe 24 air in the cooking chamber 12. In the illustrated embodiment, blower 32, 34 suck the air from the oven 12 and guide them over the helices 26, 28 of the hot during operation hot exhaust pipe 24 radially outward. From there, the heated air passes through openings in the side walls and at the top of the cooking chamber 12 again into the cooking chamber.

In the illustrated preferred embodiment, burner 20 is a multi-fuel burner that produces a vertically downward flame (not shown). The burner 20 may be operated in the preferred embodiments with diesel, petroleum and / or kerosene. In principle, however, the burner 20 could also be a gas burner or another burner.

Furthermore, for the sake of completeness, it should be pointed out that details such as "above" or "below" relate to the embodiment illustrated here and in particular to the normal operating position of the cooking appliance 10. In other embodiments and / or applications, the burner assembly 18 may also be used so that the burner 20 and / or the combustion chamber 22 have a different mounting position in which the two ends 21, 25 are for example at the same level or in the second end 25 of the combustion chamber is higher than the first end 21st

The combustion chamber 22 is here a metallic cylinder tube, which is arranged largely perpendicular to the back of the cooking chamber 12. In some embodiments, the cylinder tube is made of a V4A steel. The burner 20 and the combustion chamber 22 are in the preferred embodiment at the upper end of the cooking chamber 12, that is arranged in the region of the top of the cooking chamber 12. The combustion chamber 22 tapers at its lower end 25 and opens into an exhaust pipe 24, which is guided to a point 36 at the lower end of the cooking chamber 12. From the point 36, the exhaust pipe 24 rises again, forming the helices 26, 28. The eyes of the two coils 26, 28 are here largely parallel to each other, so that the two fans 32, 34 can be arranged with their respective axes of rotation parallel to each other in the cooking appliance 10.

With reference numeral 38 ( Fig. 3 ) is a bypass line, which extends from the upper end 21 of the combustion chamber 22 to a collecting box 40 which is arranged at the free end of the exhaust pipe 24. From the collection box 40 is another pipeline 42, which forms an exhaust gas outlet. The bypass line 38 is a substantially straight tube which is very short in relation to the exhaust pipe 26 and bridges the exhaust pipe in parallel. Thus, the bypass line is able to "short-circuit" the exhaust pipe 24.

As can be seen in the partially sectioned illustration in Fig. 4 can recognize, the bypass line 38 is a piece of pipe which is bent only at the end 44 in the region of the collecting tank 40 to open vertically from below into the collecting box 40. The line length L _{B of} the bypass line 38 is very short compared to the entire line length L _{A of} the exhaust pipe 24. Here, the line length L _{B of} the bypass line 38 was measured here as a maximum length "above everything" between the two ends 44, 46. The pipe length of the exhaust pipe 24 was measured from the lower end 25 of the combustion chamber 22 to the confluence of the exhaust pipe 24 into the collecting box 40. In the illustrated embodiment, the bypass line 38 is a straight piece of pipe over more than 80% of its length L _B , and the exhaust pipe 24 is more than ten times as long as the bypass line 38.

As in Fig. 5 is shown, the bypass line 38 has at its rear end 44 a peripheral edge 48, which opens into the collecting box 40 and 40 is slightly beyond the bottom 49 of the collecting tank. The reference numeral 50 denotes a valve cover which rests flat on the peripheral edge 48 of the bypass line 38 and thus closes the bypass line 38 at the end 44. In the illustrated embodiment, in which the burner assembly 18 is installed with a vertical orientation of the burner 20 and the combustion chamber 22 in the cooking device 10, the valve cover 50 is located horizontally on the peripheral edge 48 of the bypass line 38. As a result, the valve cover 50 is already held by gravity in the closed position, ie, the closed position of the valve cover 50 is the rule in the operation of the burner assembly 18. Only when the ignition of the burner 20, a pressure surge in the combustion chamber 22 is formed, which exceeds the ambient pressure, the valve cover 50 opens due to the overpressure in the bypass line 38. The overpressure can consequently escape past the exhaust gas line 24 through the exhaust gas outlet 42. After the overpressure subsides, the valve cover 50 falls back on the edge 48 of the bypass line 38 due to gravity. In this case, any fouling of the valve cover 50 are knocked off due to the mechanical impact.

In other embodiments, instead of a valve cover 50, a different valve closure may be used, such as a valve ball which closes the outlet end of the bypass line 38 as a rule. In further embodiments, the valve closure may be biased by means of a spring in the preferred closed position.

As you can see in the illustration in Fig. 5 can also recognize, the bypass line 38 and the exhaust pipe 24 each have an opening cross-section d ₁ and d ₂ , which are approximately equal in the preferred embodiment. Also, the exhaust outlet 42 has an opening cross-section which corresponds approximately to the opening cross-section d ₁ , d _{2 of} the bypass line 38 and the exhaust pipe 24.

Furthermore one can in the representation in Fig. 5 recognize that the collection box 40 is a largely cuboid box with a bottom side 49, in which a first tube opening 52 and a second tube opening 54 are formed side by side. The bypass line 38 opens into the first tube opening 52, wherein the peripheral edge 48 projects beyond the bottom of the collecting tank 40 in the manner already mentioned. The exhaust pipe 24 opens into the second pipe opening 54, and it ends in this embodiment, approximately flat at the level of the bottom 49. A third pipe opening 56 is formed in a side wall 58 of the collecting tank 40. The side wall 58 is largely orthogonal to the bottom 49. In the side wall 58 of the exhaust outlet 42 opens.

The burner assembly 18 can be produced very easily and inexpensively by a long tube in the in Fig. 3 illustrated manner is bent, inter alia, the two coils 26, 28 to form. A first end of the thus bent exhaust pipe 24 is welded to the remote from the burner 20 (lower) end of the combustion chamber 22. The second free end of the exhaust pipe 24 is welded in the pipe opening 54 of the collecting tank 40. Further, the bypass passage 38 is fixed with the bent end piece 44 between the combustion chamber 22 and the collecting box 40. After inserting the burner 20 in the combustion chamber 22 and attaching the pipe section 42 to the pipe opening 56, the burner assembly 18 can be installed as a compact, self-supporting heating module in the cooking appliance 10.

Claims (11)

1. A burner arrangement for a mobile heatable device, in particular for a mobile cooking device (10), comprising a burner (20) for generating a flame, comprising a burner chamber (22) into which the burner (20) with the flame ends, and comprising an exhaust pipe (24) which leads from the burner chamber (22) to an exhaust outlet (42), the exhaust pipe (24) having a defined first pipe length (L_A, further comprising a bypass pipe (38) which leads from the burner (20) to the exhaust outlet (42), wherein the bypass pipe (38) has a defined second pipe length (L_B) which is shorter than the first pipe length (L_A), characterized in that the exhaust pipe (24) is longer than the bypass pipe (38) by a factor of 10 or more, and characterized by a valve closure (50) which usually closes the bypass pipe (38), wherein the valve closure (50) is pressure controlled in such a manner that it automatically opens the bypass pipe (38) at a defined overpressure in the burner chamber (22), such that the bypass pipe (38) opens when the burner (20) is ignited, and bypasses the exhaust pipe (24), wherein the bypass pipe (38) is closed during stationary operation of the burner (20).
2. The burner arrangement according to claim 1, characterized in that the bypass pipe (38) has an end with a circumferential edge (48), wherein the valve closure (50) usually rests on the circumferential edge (48).
3. The burner arrangement according to one of claims 1 or 2, characterized in that the bypass pipe (38) and the exhaust pipe (24) each have an opening cross section (d₁, d₂), wherein the opening cross sections (d₁, d₂) are substantially equal in size.
4. The burner arrangement according to one of claims 1 to 3, characterized in that the burner chamber (22) is a substantially cylindrical tube having a first end (21) and a second end (25), wherein the burner (22) extends into the tube at the first end (21), and wherein the exhaust pipe (24) starts at the second end (25) of the burner chamber (22).
5. The burner arrangement according to one of claims 1 to 4, characterized in that the exhaust pipe (24) forms at least one loop (26) which winds around a first open eye (30).
6. The burner arrangement according to claim 5, characterized in that the exhaust pipe forms a second loop (28), which winds around a second open eye (30).
7. The burner arrangement according to claim 5 or 6, characterized in that the at least one loop (26) is arranged adjacent to the burner chamber (22).
8. The burner arrangement according to one of claims 1 to 7, characterized in that the bypass pipe (38) is a substantially straight piece of tube.
9. The burner arrangement according to one of claims 1 to 8, characterized by a collection container (40) having a first tube opening (52), having a second tube opening (54) and having a third tube opening (56), wherein the bypass pipe (38) ends in the first tube opening (52), wherein the exhaust pipe (24) ends in the second tube opening (54), and wherein the third tube opening (56) leads to the exhaust outlet (42).
10. A cooking device for cooking food, in particular a mobile field kitchen, comprising a device housing (13) including a cooking space (12) for receiving food, comprising a burner arrangement (18) for generating heated air, comprising a fan (32, 34) for circulating the heated air through the cooking space, and comprising an electrical control device controlling at least the burner arrangement (18) and the fan (32, 34) in response to a cooking program stored in the control device, characterized in that the burner arrangement (18) is configured in accordance with one of claims 1 to 9.
11. The cooking device according to claim 10, characterized in that the exhaust pipe (24) winds around the fan (32, 34).

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