EP1767859A2 - Double stove - Google Patents

Abstract

The stove has a fire chamber (5) and an exhaust gas traction (6) formed from a fireclay and forming a stove core. The core is surrounded in all sides by an encircling wall. A warm air stove (11) is arranged in direct proximity to a base stove (1). The chamber and traction are formed from metal and form a heating unit (12). An exhaust gas outlet (8) of the base stove is attached at a chimney, where the outlet and an air film around the core are connectable over a hermetically sealed air cover (21) with the air film around the heating unit. The film is connected by the cover with ambient air. An independent claim is also included for a method for operating a double stove.

Description

The invention relates to a double oven, consisting of a basic oven with a fire chamber of fireclay and flue gas from fireclay, which form a furnace core, which except for a fire door, a flue gas outlet, several columns below the firebox and the flues on all sides of a wall of firebricks is surrounded, which forms a uniformly thin layer of air towards the furnace core.

The state of heating technology in residential buildings is primarily central heating systems with automatic supply of fuel gas, oil and increasingly wood, which can be fed by pressing in small pellets with automatic conveyors. However, there is still, and to a significant extent, the human need to manually supply the fuel to the heater and / or to have visual contact with the flame. An advantage of this heating device is that irregularly shaped and therefore not automatically supplied with reasonable effort fuel can be burned with relatively little effort.

According to the current state of the art for wood burning systems in living spaces, two principles have been developed in particular: The basic oven and the hot air oven, also called fireplace. The basic structure of both ovens is very similar. The fuel is introduced through a fire door into the firebox and burned there. The resulting flue gas pulls out of the fire chamber through flues in the flue gas outlet, which is connected to the chimney, which ensures the further transport of the flue gas into the environment.
Fire chamber and flues emit heat and heat the air layer in contact with them. The unit of fire chamber and flue is referred to in the basic furnace as "furnace core" in hot air oven, the term "heating insert" is common.
Common to both principles are that furnace core or heating insert is surrounded by a wall of fireclay. Between the wall and the core or insert there remains a uniform thickness of air which is only interrupted by the opening for the fire door, the columns and the flue gas outlet. Here ends the similarities between the two furnace principles.

The following differences are relevant for the operating principle: The furnace core of the base furnace consists of chamotte or possibly another material with the same heat resistance and heat storage capacity. In comparison to the heating of the hot air oven, the furnace core is considerably heavier, has a considerably larger heat storage capacity and a significantly higher heat transfer resistance from the flame to the surrounding air layer. The large mass and the high heat transfer resistance result in the marketable basic furnaces need a heating time in the order of 1.5 to 2 hours, but store a lot of heat as a preference. Typical base furnaces maintain a sufficient heat for heating for 12 to 24 hours beyond the burning off of a single fuel charge.

This heat energy is transmitted to 60% as radiant heat and only 40% through contact with the room air and its convection (turbulence).

Thanks to the high combustion temperature of 800 - 1000 ° C, the introduced firewood is almost completely burned. Therefore Even with daily use usually only twice a year, the emptying of the combustion residues (ash) required. From this almost complete combustion down to the "reason", the term "basic furnace" is derived.

Completely different characteristics has the "hot air oven" or "fireplace" on. Its heating element is basically made of metal, which is why the mass of the heating insert is much lower than in the base furnace and reaches the continuous operating temperature after about ¼ hour heating time in typical hot air fireplaces. The heat transfer resistance of metal is considerably lower than with chamotte; why the heat energy of the fire is transmitted much faster to the ambient air.

Thanks to these good heat transfer properties, domestic hot water heating is only a useful accessory for a hot air oven. According to the current state of the art flue gas service water heat exchangers are basically constructed of metal. They are traversed by the flue gas and thereby heat water, which flows through the heat exchanger in a second circuit.

The working principle of the hot air oven differs from the basic oven in that 70 - 80% of the heat energy is given off by convection and only 20 - 30% as radiant heat through the wall. This high proportion of convection is due to the fact that due to the low heat transfer resistance of the metal compared to chamotte the air layer around the heating insert rises very quickly to such high temperatures that the air has to be removed.
Since the total amount of air around the heater around is relatively small and there are no areas between heating and walling in which the heated air could be cooled down again, it must be led out and supplied to the air of the room to be heated as an energy source for the heating energy. This also creates a turbulence in the air in the heated room.

A disadvantage of this heating principle is that the ever-present dust together with insects living therein, such. As mites and their feces, whirled up and distributed in space. In particular against the feces of the mites but also against the fine dusts, more and more people are allergic. The impingement of these foreign bodies and / or toxins on the body is the physics not quite correct, but properly classified as unpleasant and uncomfortable with the colloquial buzzword "dry heating air".

Another disadvantage of the convection heating is that their efficiency compared to the radiant heat is significantly worse, because not only the object to be heated, but also the air between the heating and object is heated. To achieve a comparable heating effect, therefore, the surface temperature of a radiant heater can be up to 5 ° C lower than the surface of a convection working Heizköpers. The considerably lower temperature of a radiator working primarily with radiation causes considerably less air turbulence and accordingly much less contamination of the room air. For these reasons, radiant heating is subjectively classified as much more comfortable and pleasant compared to convection heating.

The high proportion of radiated heat energy is therefore a decisive advantage of the basic furnace, from which also the much better efficiency of up to 93% results, which is clearly superior to the hot air oven with a typical efficiency of about 55%.

Another difference between the two oven principles is the visualization of the fire. Since the basic air supply must be controlled very carefully and since the base furnace should have as few thermodynamic weak points to the outside, it corresponds to the current state of the art that the combustion air is supplied through separable areas of the fire door. The combination of this mechanism with a multi-layered glass plate construction, which withstands the high combustion temperatures and still has acceptable heat transfer resistance, is considerably more expensive compared to a non-transparent fire door for basic furnaces. The surcharge is on the order of an additional warm air heating insert with a (in this case) considerably less expensive, transparent fire door.

From the aforementioned comparisons, the question arises of a furnace which combines the advantages of both principles. An attempt in this direction is the so-called "combi oven". It consists of the heating insert of a hot air oven, but with very short flues of metal. The metal flues are followed by a flue gas chimney based on the principle of the base furnace. This area is used to store the heat. An advantage of the combination oven is that a heat exchanger can be integrated for DHW heating. Compared to a hot air oven with an efficiency of 55%, the typical efficiency of combi ovens is about 75% a significant gain.

The invention has set itself the task of creating an oven that can achieve a much higher efficiency than the combi oven, offers the option to integrate a hot water heat exchange and makes the fire visually advantageous visible.

For this purpose, the invention teaches a double oven, characterized in that in the immediate vicinity of the base furnace, a hot air oven is arranged, consisting of a fire chamber made of metal and flues of metal, which form a heating element, which except for a fire door, a flue gas outlet and several supports below the Fire chamber and the flues is surrounded on all sides by a wall of firebricks, which forms a uniformly thick, second layer of air for heating use, the flue gas outlet of the base furnace is connected to the same chimney, as the flue gas outlet of the hot air oven and the first layer of air around the furnace core of the furnace around at least one airtight sealable flap with the air layer around the heating element of the hot air oven is connectable and this layer of air can be connected via an airtight sealable flap with the ambient air.

Such a double oven offers significant advantages in comparison with the previously known principles. The use of standard elements both for the furnace core of the base furnace and for the heating element of the hot air oven ensures functional reliability during heating and during continuous operation of the fire as well as in the flue gas duct.

It is easy to understand that solitary operation of the basic furnace part achieves an efficiency that fully corresponds to the current state of the art, ie more than 90%.

A further improvement is achieved by the fact that by opening the air damper between the two layers of air base furnace and hot air oven and by closing the air outlet from the hot air oven together with the closing of the fire door of the hot air oven, the mass of firewood bricks to be heated of the basic furnace to the mass of the heating insert and its walling is increased. As a result, the available radiation surface and thus the radiation component continue to rise, which further increases the efficiency of the overall furnace system.

Another economic advantage results from the fact that for a given, required heating power of the basic furnace can be made smaller, because it can be supplemented by the heating power of the hot air fireplace in a basic furnace similar operating mode, so that in this mode in both fire chambers with fuel high temperature is burned. As with the aforementioned method with only one fire in the base furnace, the air layers of both ovens must be connected by opening the flap (s) in this operating condition, any existing window in the firing door of the hot air oven should be closed by a thermally insulating flap and the air outlet opening in the air layer around the hot air oven around airtight be closed. The characteristic feature of this mode is that the air layer acts as an insulator at the beginning of operation. Preventing convection prevents premature cooling of the furnace core. After burning the fire stored in the furnace core thermal energy is stored in the total mass of the furnace core, then released over the air layer, especially as radiant heat comparatively slowly to the outer wall and from this in turn as radiant heat to people in the room to be heated or passed on to other objects that are near the stove. A Enlargement of the surface of the kiln plant by the additional co-used walling of the hot air oven brings a further improvement in the subjective perception of the heating effect and in the objective efficiency of the overall system.

However, the double oven still allows for other advantageous modes of operation. So z. B. the hot air oven are operated solitary. Within a very short heat-up time, it produces warm air, whereby the air connection to the base oven should be closed, if the basic oven is not fired. For sufficient convection, of course, the air outlet openings of the hot air oven must be brought into the "open" position. A possibly existing blower to increase the circulation further shortens the heat-up time. In a short time the hot air oven produces the required heat. An additional advantage (depending on the design) is that the fire can be visually experienced by a window that may be present in the fire door.

A decisive advantage over previous principles, the double oven offers, if he has to compensate for a comparatively very high temperature difference in a comparatively short time. This task arises in a cooled building during the winter, which is to be heated at short notice.

This object is achieved by the double open according to the invention by the operating mode "rapid heating" in which in addition to the hot air fireplace and the basic furnace is fired. By opening the air damper between the two air layers, convection also occurs in the air layer around the furnace core of the base furnace. The heat energy generated in the firebox of the base furnace quickly through this heated air of the air layer of the hot air oven supplied and transported from the air outlet opening into the room inside.

This operating mode is not typical for the basic oven, which is why in this mode of operation "rapid heating" the efficiency can not be as high as it is in continuous operation. For this reason, it is recommended that after reaching an acceptable room temperature as soon as possible on the. Operating mode "long-term full load" is changed over. As mentioned previously, the efficiency increases significantly in this mode.

Another useful and inventive accessory is the formation of the fire door 17 as a transparent glass plate. In contrast to a transparent design of the fire door in front of the base furnace, this glass plate is relatively inexpensive, since it does not have to thermally insulate. A good passage of heat energy through the disc is rather welcome in the hot air oven, because it increases the proportion of rapidly available radiant energy further. The transparent fire door has in the hot air oven so only the function to separate the ambient air from the firebox, which is why the requirements are not extremely high. In addition, a fire in the fire chamber always absorbs a lot of air and burns in this way small amounts of air that pass the transparent fire door into the firebox, with. The design criterion for the glass plate in front of the firebox of the hot air oven is therefore only a sufficient temperature resistance.

The functionality of the thermal insulation is better, according to the recommendations of the invention, displaced into an opaque door separate from the glass plate, which can be pivoted as a second level in front of the glass plate. The desired insulating effect is significantly lower with materials other than glass To achieve effort. Doors with good insulation, sufficient temperature resistance and desirable airtightness are produced in the prior art in numerous variants and therefore need not be further described here.

With this extra, between the extremes of "rapid heating" and the "long-term full load", the type of heating referred to here as "optically optimized continuous operation" is a sensible compromise. Here, the focus of heat generation in the base furnace; he is charged with such a fuel quantity as is necessary to achieve the target temperature, the minimum feed rate must not be fallen below. The basic oven is not connected to the hot air oven in this operating mode, which is why all air dampers between the basic oven and the hot air oven are closed.

The hot air oven has in this mode only the task of creating a visually pleasing flame effect through a window in his fire door. Therefore, it should only be filled with such a small amount of fuel in the firebox that the sight of the flame can be classified as still sufficiently subjective. Accordingly, the radiated heat from the hot air oven heat is comparatively low. In the interest of the highest possible efficiency convection should be as low as possible. Therefore, it is advisable to open the air outlet openings of the hot air oven only to a part.

The multitude of the different modes of operation described above is probably the most important advantage of the double oven principle. It allows on the one hand in continuous operation an extremely high efficiency, on the other hand a very fast heating, so a comparatively extremely low heat rise time in the room to be heated and as Compromise in continuous operation an additional visual effect through the viewing window of the hot air oven.

For a further improvement according to the invention, various features are proposed and recommended. For an improvement in the efficiency of the optically optimized continuous operation, it is advantageous if the air damper can be set to connect the air layer of the hot air oven with the ambient air in different opening stages. Another possibility is the opening and closing of the flap in the shortest possible intervals. Although this method saves the additional effort for an adjustable air damper in various stages, but for manual operation is not practical, but in principle only useful for connection to ongoing active electronic controls. But even in this case, a continuously adjustable damper would be advantageous because the noise of the damper operation is eliminated and the quality of control is significantly improved.

A further advantageous embodiment of a double furnace according to the invention relates to the connection of the two layers of air around the base furnace or around the hot air oven. For the functioning of all modes of operation according to the invention, it is necessary that the two layers of air are either in communication or thermally and / or fluidically separated from one another by means of a suitable device. In the simplest case, in which the masonry of the base furnace and the hot air oven do not touch, already sufficient a pipe which is hermetically sealed by a flap or opened.

A functionally justified, further variant is to bring both ovens as close together as possible to each other and that way, that their walls have the largest possible, common contact surface. It makes sense not only to put the two walls together form-fitting and mortar in the area of this contact surface, but to build a single, shared so-called "contact wall" instead of a two-part wall area. The thinner the wall, the more intense the heat exchange between the two ovens.

For the simplest case, that neither an airtight sealable flap is provided in the contact wall nor a foldable or wegschiebbare thermal insulation layer is seated on the contact wall, but according to the invention a functional added value from the combination of base furnace and hot air oven can be seen. In the operating modes "continuous full load" and "optically optimized continuous operation", in principle a connection of the two air layers around the furnace core of the base furnace and around the heating insert of the hot air oven is optimal. The effect of this air connection can be at least partially replaced by the fact that the contact wall works like an air / air heat exchanger. As a result, thermal energy can pass from one layer of air into the other layer of air.

For the "fast heating" operating mode, together with the configuration of a rather thin contact wall without flaps, it is advisable to ensure sufficient convection in the air layer around the furnace core of the basic furnace. For this purpose, a fan is suitable in principle, the impeller and its drive must be sufficiently temperature-resistant. Alternatively, the motor can be arranged outside the air layer and transmit the mechanical energy to the impeller arranged in the air layer via an air-tight passage of the shaft.

Another alternative for generating air convection during the rapid heating phase is to set a (temperature-resistant) impeller through a sufficiently large dimensioned bimetallic element in rotation. The transfer of thermal energy by means of a bimetallic element into mechanical energy on the impeller, the convection is amplified within the air layer with each heating and each cooling of the furnace.

According to the invention, an alternative to dispensing with the louvers between the two air layers is a very thin wall, the so-called "contact wall", which operates as an air / air heat exchanger and transfers energy from one to the other air layer. The more heat energy is exchanged over the contact wall, the more advantageous the double oven operates in the operating modes "rapid heating" and "long-term full load".

Therefore, it is a further improvement of the principle of the "contact wall" to replace it with a "touch metal plate" because metal has a lower specific heat transfer resistance than ceramic. A reduction of the heat transfer resistance of the entire "touch metal plate" is achieved by ripping, nubs or other enlargements of the surface on at least one side, because it improves the heat transfer from the air into the metal and from there back into the air.

• Insgesamt beschreibt die Erfindung fünf verschiedene Betriebsarten:
  • In den drei Betriebsarten "Schnellerwärmung", "Langzeitvolllast" und "optisch optimierter Dauerbetrieb" sind beide Feuerkammern beschickt, dazu kommt der solitäre Betrieb des Grundofens oder des Warmluftofens. Jede Betriebsart wird optimiert, indem Luftklappen und thermische Isolationselemente geöffnet bzw. geschlossen werden. Für die Luftklappe zwischen der Außenluft und der Luftschicht um den Heizeinsatz des Warmluftofens herum wird sogar eine Einstellung in Stufen bevorzugt. Wenn all diese Regelelemente mit einem z. B. elektrischen Antrieb versehen sind und wenn all diese Antriebe in einer gemeinsamen, elektronischen Steuerung zusammengeführt sind, kann die Steuerung alle Regelungselemente betriebsartgemäße einstellen. Der Benutzer kann in dieser erfindungsgemäßen Ausstattungsvariante den Doppelofen über Tasten, Schalter oder über einen Berührungsbildschirm an der Steuerung einstellen.

In the "optically optimized continuous operation" operating mode, on the other hand, a heat transfer between the two air layers of the base furnace and the hot air oven is not welcome. For this mode, the invention recommends an additional thermal insulation layer, which can be folded or pushed up against the contact wall or to the contact metal plate. In optically optimized Continuous operation prevents this insulation layer from cooling down too quickly:

• Overall, the invention describes five different operating modes:
  • In the three operating modes "rapid heating", "long-term full load" and "optically optimized continuous operation", both fire chambers are charged, plus the solitary operation of the basic furnace or the hot air oven. Each operating mode is optimized by opening and closing air dampers and thermal insulation elements. For the air damper between the outside air and the air layer around the heating element of the hot air oven around even a setting in stages is preferred. If all these rule elements with a z. B. electric drive are provided and when all these drives are brought together in a common, electronic control, the controller can set all control elements mode of operation. The user can set the double oven via buttons, switches or via a touch screen on the controller in this equipment variant of the invention.

A further expansion stage according to the invention is at least one sensor each for detecting the temperatures in both air layers and in the outside air, which is connected to the controller. Through these sensors, the control closes control loops, which makes it possible in this expansion stage that the user selects operating mode and temperature at the control and, as a manual operation, only feeds the combustion chambers with fuel. The invention expressly includes the combination of a double furnace with automatic fuel delivery for the base furnace and / or the hot air oven.

A further advantageous embodiment of the invention is the integration of a flue gas hot water heat exchanger in the Flue gas duct of the hot air oven. As mentioned above, according to the prior art, such heat exchangers are basically constructed of metal and designed as accessories for the heating element of the hot air oven. The integration in the basic furnace is not useful in a double oven, because it would noticeably lower the maximum achievable efficiency of the basic oven. This problem shows us the well-known combination oven yes.

Another advantage of the allocation of service water heating to the hot air oven is that it can be heated there much faster by a separate fire than in the base furnace.

• Ein Teil der erfinderischen Innovation ist, dass durch die Wand zwischen den beiden Luftschichten Wärme vom Grundofen in den Luftraum um den Warmluftofen gelangt und dort über die Ummauerung des Warmluftofens ebenfalls abstrahlen kann. Gegenüber einem allein stehenden Grundofen wird damit die Oberfläche und der Anteil an Strahlungswärme vergrößert. Dadurch steigt der Wirkungsgrad im Dauerbetrieb noch etwas an, nach Stand der Technik auf über 90 %. Ein staubfreier Dauerbetrieb mit Eignung für Allergiker ist möglich.
• Der zweite Teil der erfinderischen Innovation ist eine wenigstens so kurze Anheizzeit wie bei einer reinen Warmluftheizung.
• Der dritte Teil der erfinderischen Innovation ist, dass im Vergleich zu einem Grundofen mit gläserner Feuertür der zusätzliche Vorteil der kurzen Anheizzeit durch den Warmluftkamin in der Gesamtkalkulation keinen Aufpreis erfordert.
• Der vierte Teil der erfinderischen Innovation ist, dass wie beim Kombiofen mit wirkungsgrad von 75 % eine Warmwassererwärmung integriert werden kann, aber dafür keine Verschlechterung des Wirkungsgrades der Raumbeheizung in Kauf zu nehmen ist.
• Der fünfte Teil der erfinderischen Innovation ist, dass mit der Möglichkeit einer elektronischen Steuerung von Luftklappen und Isolationstüren der Regelkomfort einer Holzheizungsanlage erreicht wird,

wobei im Vergleich dazu erheblich mehr direkte Strahlungswärme und erheblich mehr optischer Komfort geboten wird.A double oven according to the invention thus offers numerous advantages, which are to be summarized again below:

• Part of the inventive innovation is that passes through the wall between the two layers of air heat from the base furnace in the air space to the hot air oven and there also can radiate on the wall of the hot air oven. Compared to a standalone basic furnace so that the surface and the proportion of radiant heat is increased. As a result, the efficiency in continuous operation increases somewhat, according to the prior art to over 90%. A dust-free continuous operation with suitability for allergy sufferers is possible.
• The second part of the inventive innovation is an at least as short heat-up time as in a pure warm air heating.
• The third part of the inventive innovation is that, in comparison to a glass-bottomed fire-place basic oven, the additional advantage of the short heat-up time through the hot-air fireplace in the total costing does not require an extra charge.
• The fourth part of the inventive innovation is that, as with the Kombiofen with efficiency of 75%, a hot water heating can be integrated, but for no deterioration in the efficiency of space heating is to be accepted.
• The fifth part of the inventive innovation is that with the possibility of electronic control of louvers and isolation doors, the control comfort of a wood heating system is achieved,

In comparison, considerably more direct radiant heat and significantly more visual comfort is offered.

• Figur 1: Querschnitt durch einen Doppelofen, wobei Grundofen und Warmluftofen nur durch zwei Luftrohre miteinander verbunden sind;
• Figur 2: Querschnitt durch Doppelofen mit einer für beide Öfen gemeinsamen Berührungsmetallplatte;
• Figur 3: Tabelle für die Konfiguration der sieben wesentlichen Elemente in fünf verschiedenen Betriebsarten.

In the following, further details and features of the invention will be explained in more detail by way of examples. However, the examples shown are not intended to limit the invention, but only to explain. In a schematic representation:

• Figure 1: cross section through a double oven, wherein basic oven and hot air oven are connected to each other only by two air pipes;
• FIG. 2 shows a cross section through a double oven with a contact metal plate common to both ovens;
• Figure 3: Table for the configuration of the seven essential elements in five different operating modes.

The figures show in detail:

In Figure 1, a double oven with opposite fire chambers is shown in section. It consists of the basic furnace 1 on the left in the picture and the hot air oven 11 on the right in the picture. For the sake of an improved Clarity, the reference numerals are chosen so that in principle the same elements of basic and hot air oven wear the same reference numerals in the first place. For distinction, the reference numerals of the ten most important elements of the hot air oven in the second place have a 1; So they differ in value by 10.

On the left in the picture, the furnace core 2 of the basic furnace 1 can be seen as a rather massive block. It consists of the firebox 5 and the adjoining flues 6. In the firebox 5 a log fire is located. The smoke rising therefrom runs from the firebox 5 meandering through the flues 6 of the furnace core 2 and is guided by the flue gas outlet 8 in the chimney 10.

In principle, the same structure consists of the hot air oven from the heating element 12, which consists of the fire chamber 15 made of metal (marked by a thick line) and the adjoining metallic flue gas ducts 16. The flue gas of the fire in the fire chamber 15 meanders here through the flues and escapes through the flue gas outlet 18 in the same chimney 10th

In Figure 1 it is clear that the fire door 15 in front of the fire of the hot air fireplace is significantly larger than the door 7 of the base furnace. Also, the ash box 34 below the fire is the hot air oven 11 considerably larger than the base furnace 1, since the hot air oven 11 produces more ash than the base furnace due to its poorer combustion and low operating temperature.

In the middle of FIG. 1 it can be seen how close the wall 4 of the base furnace 1 and the wall 14 of the hot air oven 11 are standing together. For the connection of the two air layers 3 and 13, a total of two air ducts are shown in Figure 1, which can be hermetically sealed by the flaps 20. In Figure 1, they are shown in the closed state. All other flaps and doors are drawn in their closed state. For the assignment of the respective states of flaps and doors to the five different operating modes, the table in FIG. 3 has been prepared.

Figure 2 shows the cross section through a double oven consisting of the same type of basic oven 1 and hot air oven 11. The main difference is that the two ovens have been brought together as close as possible; the walling 4 and 14 omitted in the contact area of the two ovens, instead, a contact plate 24 is shown in section. On this plate is also shown in section thermal insulation layer 25. It is not shown that this insulation layer 25 can be folded down and / or displaced.
In Figure 2 it is clear that the air layers 3 and 13 through the contact metal plate 24 can easily exchange heat energy with each other. However, only when the thermal insulation layer 25 is folded away from the touch metal plate 24 or pushed away.

As a further, inventive extra flue gas / hot water heat exchanger 32 is located in the flue gas ducts 16 of the hot air oven 11.
As a further feature according to the invention, FIG. 2 shows the central electronic control 27. Shown is their connection to a total of three pieces of sensors 26 for the purpose of detecting the temperature of the outside air, the air layer 3 in the base furnace 1 and the air layer 13 in the hot air oven 11. To a complete loop training include servo drives, which operate the flaps and doors of the double oven, these are also not shown in Figure 2 for reasons of space. Only with these additional servo drives a fully automatic control of the furnace by the electronic central control 27 is possible.

• Grundofen solitär
• Schnellerwärmung
• Langzeit-Volllast
• optisch optimierter Dauerbetrieb
• Warmluftofen solitär
  die Stellung von sieben wichtigen Elementen von Grundofen 1 und Warmluftofen 11. Es sind die Befeuerung der Feuerkammer 5 und dann in der Berührungszone die jeweilige Stellung der Luftklappe 20 zwischen den Luftschichten 3 und 13, sowie die Stellung der Thermoisolation 25 auf der Berührungsmetallplatte 24. Zu den Betriebszuständen gehört auch die Konvektion in der Luftschicht 13 des Warmluftofens. Deren Unterstützung durch ein Gebläse ist insbesondere in den Betriebsarten "Schnellerwärmung" und "Warmluftofen solitär" sehr wichtig, wofür die Tabelle Vorschläge enthält.

FIG. 3 shows a table. It contains for the five operating modes

• Basic oven solitary
• rapid heating
• Long-term full load
• optically optimized continuous operation
• Warm air oven solitary
  the position of seven important elements of the basic furnace 1 and hot air oven 11. It is the firing of the firebox 5 and then in the contact zone the respective position of the louver 20 between the air layers 3 and 13, and the position of the thermal insulation 25 on the contact metal plate 24. Zu The operating conditions also include the convection in the air layer 13 of the hot air oven. Their support by a blower is very important, especially in the modes "rapid heating" and "hot air oven solitary", for which the table contains suggestions.

Essential for the hot air oven is the position of the air damper 21 between air layer 13 and outside air. The same applies to the also entered in the table thermal door in front of the firebox 15 of the hot air oven. Especially in the basic furnace solitary and long-term full load modes, it prevents unwanted radiation of heat energy through the viewing window of the fire door of the hot air oven 11.

LIST OF REFERENCE NUMBERS

• 1 = basic oven
• 2 = Furnace core of the basic furnace 1, consisting of fire chamber 5 and flue gas trains. 6
• 3 = air layer thin, between furnace core 2 and wall 4
• 4 = Wall around furnace core 2
• 5 = fire chamber of the base furnace 1 of chamotte
• 6 = flues of the base furnace 1 from chamotte
• 7 = fire door in front of firebox 5
• 8 = flue gas outlet from the flue gas ducts 6 to the chimney 10
• 9 = supports of the furnace core 2
• 10 = chimney
• 11 = hot air oven
• 12 = heating insert, consisting of fire chamber 15 and flue gas 16
• 13 = air layer thick, between heating element 12 and wall 14
• 14 = walling
• 15 = fire chamber of the hot air oven 11 made of metal
• 16 = flues of metal
• 17 = fire door in front of firebox 15
• 18 = flue gas outlet from the flue 16 to the chimney 10
• 19 = supports of the heating insert 12
• 20 = flap, airtight sealable for connecting air layer 3 in the base furnace 1 with air layer 13 in the hot air oven 11
• 21 = flap, hermetically sealed to connect the air layer 13 of the hot air oven 11 with the outside air
• 22 = thermal insulation door, outside the fire door 17 arranged
• 23 = contact wall between air layer 3 and air layer 13
• 24 = touch metal plate, touches both air layer 3 and air layer 13th
• 25 = thermal insulation layer on touch metal plate 24, hinged and / or displaceable
• 26 = sensors for temperatures of the air layer 3, the air layer 13 and the ambient air
• 27 = central, electronic control
• 28 = circulating fan in air layer 3 or 13
• 29 = fast heating mode
• 30 = Long-term full load mode
• 31 = Optically optimized continuous operation
• 32 = flue gas leaving water heat exchanger
• 33 = ash door
• 34 = ash box

Claims (14)

Double oven, consisting of a basic oven 1 with a firebox 5 made of chamotte and flue gas ducts 6 made of chamotte, which form a furnace core 2, - Which except for a fire door 7, a flue gas outlet 8, a plurality of supports 9 below the firing chamber 5 and the flues. 6 - surrounded on all sides by a wall 4 of firebricks, - Which forms a uniformly thin air layer 3 towards the furnace core 2 characterized in that
in the immediate vicinity of the base furnace 1, a hot air oven 11 is arranged, consisting of a metal firebox 15 and metal smoke flues 16 forming a heating element 12, - Which except for a fire door 17, a flue gas outlet 18, a plurality of supports 19 below the firing chamber 15 and the flues 16 - surrounded on all sides by a wall 14 of firebricks, - Which forms a uniformly thick second air layer 13 towards the heating insert 12 in which - The flue gas outlet 8 of the base furnace 1 is connected to the same chimney 10, as the flue gas outlet 18 of the hot air oven 11 and - The first air layer 3 is connected to the furnace core 2 of the Grundofen1 around at least one airtight sealable flap 20 with the air layer 13 to the heating element 12 of the hot air oven 11 and - The air layer 13 is connected via an airtight sealable flap 21 with the ambient air. Double oven according to claim 1
characterized in that
the flap 21 has different opening levels. Double oven according to previous claims
characterized in that
In front of the fire chamber 15 made of metal, a fire door 17 in a transparent embodiment and on the outside of an additional thermal insulation door 22 is arranged. Double oven according to previous claims
characterized in that
the base furnace 1 and the hot air oven 11 are arranged so close to each other that the minimum thickness of the air layers 3 and 13 is not exceeded - And the walls 4 and 14 are vermörtelt as large as possible with each other or alternatively transition into the largest possible, common contact wall 23, which touches the air layer 3 on one side and the air layer 13 on its other side. Double oven according to the preceding claims
characterized in that
the contact wall 23 is thinner than 3 cm. Double oven according to the preceding claims
characterized in that
the contact surface between the air layers 3 and 13 is formed as a contact metal plate 24 Double oven according to the preceding claim 5
characterized in that
the contact metal plate 24 has ribs, nubs or other surface enlargements on at least one side Double oven according to the preceding claims
characterized in that
on the contact metal plate 24, a thermal insulation layer 25 is arranged, which is hinged and / or wegschiebbar. Double oven according to previous claims
characterized in that
the louvers 20 and / or 21 and / or the thermal insulation door 22 are coupled in front of the fire door 17 and / or the thermal insulation layer 25 in front of the contact metal plate 24 with electric drives
and at least one respective sensor 26 for the temperatures of the air layers 3 and 13 and for the temperature of the ambient air with a central electronic control 27 are connected. Double oven according to previous claims
characterized in that
at least in one of the two air layers 3 and 13, a circulating fan 28 is integrated, which can be activated via an external power source and connected to the controller 27. Double oven according to previous claims
characterized in that
in the flue gas duct of the hot air oven 11 a flue gas hot water heat exchanger 32 is integrated, which is arranged within the wall 14. Method for operating a double furnace according to the preceding claims in the operating mode rapid heating 29
characterized in that - Burned in both fire chambers 5 and 15 fuel and the air flaps 20 between the two air layers 5 and 15 or the thermal insulation layer 25 are completely open, and the fan 28 in the air layer 15 is activated, - And the air damper 21 between the air layer 15 and the ambient air are completely open, and - The thermal insulation door 22 is opened in front of the fire door 17. Method for operating a double oven according to the preceding claim 12 in the mode of long-term full load 30
characterized in that - The louver (s) 21 between the air layer 15 and the ambient air and - The thermal insulation door 22 are closed in front of the fire door 17. Method for operating a double furnace according to the preceding claims in optically optimized continuous operation mode 29
characterized in that - In the firebox 5, the amount of fuel required to achieve the target temperature is burned and - In the fire chamber 15 only as much fuel is burned, as is required for a visually pleasing fire and fire - The air damper 20 and the thermal insulation layer 25 between the two air layers 5 and 15 is closed and - The fan 28 is separated in the air layer 15 from its power source and - The louvers 21 between the air layer 15 and the ambient air only slightly, but are opened in accordance with the size of the fire in the firebox 15, and - The thermal insulation door 22 is opened in front of the fire door.

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